<PAGE>

                    U.S. SECURITIES AND EXCHANGE COMMISSION
                            Washington D.C.  20549

                                FORM 10-QSB/A

(Mark One)
[X] QUARTERLY REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF
     1934


               For the quarterly period ended     June 30, 1999
                                              -----------------


[ ] TRANSITION REPORT UNDER SECTION 13 OR 15(d) OF THE EXCHANGE ACT



     For the transition period from             to
                                    ------------  -----------


       Commission file number   0-17576
                             ----------


          WINDSOR PARK PROPERTIES 6, A CALIFORNIA LIMITED PARTNERSHIP
   ------------------------------------------------------------------------
       (Exact name of small business issuer as specified in its charter)

<TABLE>
<CAPTION>

<S>                                                                 <C>
                        California                                              33-0299846
 ------------------------------------------------------------         -------------------------------
(State or other jurisdiction of incorporation or organization)       (IRS Employer Identification No.)


                              6160 So. Syracuse Way, Greenwood Village, Colorado 80111
                         ------------------------------------------------------------------
                                     (Address of principal executive offices)

</TABLE>
                                (303) 741-3707
                           -------------------------
                          (Issuer's telephone number)



Check whether the issuer (1) filed all reports required to be filed by Section
13 or 15(d) of the Exchange Act during the past 12 months (or for such shorter
period that the registrant was required to file such reports), and (2) has been
subject to such filing requirements for the past 90 days.
Yes  (x)     No  ( )
     ---         ---

Transitional small business disclosure format (check one): Yes [ ]  No [X]
<PAGE>

                               TABLE OF CONTENTS

                                    PART I
                                    ------


                                                               Page

Item 1.   Financial Statements                                    2

Item 2.   Management's Discussion and Analysis of Financial
          Condition and Results of Operations                     8

                                    PART II


Item 6.   Exhibits and Reports on Form 8-K                       11

          SIGNATURE                                              12
<PAGE>

                                     PART I


Certain matters discussed under the Management's Discussion and Analysis of
Financial Condition and Results of Operations and elsewhere in this Quarterly
Report on Form 10-QSB/A may constitute forward-looking statements, and as such
involve known and unknown risks, uncertainties and other factors which may cause
the actual results, performance or achievements of Windsor Park Properties 6, a
California Limited Partnership, to be materially different from any future
results, performance or achievements expressed or implied by such forward-
looking statements.

                                       1
<PAGE>

Item 1.    Financial Statements
-------
                           WINDSOR PARK PROPERTIES 6
                           -------------------------
                      (A California Limited Partnership)
                                 BALANCE SHEET
                                 -------------
                                  (unaudited)

<TABLE>
<CAPTION>
                                                                                      June 30, 1999
                                                                              --------------------------------
ASSETS
------
<S>                                                                           <C>
Property held for investment:
  Land                                                                         $                       325,000
  Buildings and improvements                                                                         2,464,700
  Fixtures and equipment                                                                                37,000
                                                                              --------------------------------
                                                                                                     2,826,700
Less accumulated depreciation                                                                       (1,216,500)
                                                                              --------------------------------
                                                                                                     1,610,200

Investments in joint ventures and limited partnerships                                               4,839,500
Cash and cash equivalents                                                                              341,000
Other assets                                                                                             7,300
                                                                              --------------------------------
Total Assets                                                                   $                     6,798,000
                                                                              ================================


LIABILITIES AND PARTNERS' EQUITY
--------------------------------

Liabilities:
  Accrued expenses                                                             $                        87,000
  Due to General Partner and affiliates                                                                 14,500
  Tenant deposits and other liabilities                                                                 11,200
                                                                              --------------------------------
Total Liabilities                                                                                      112,700
                                                                              --------------------------------
Partners' equity:
  Limited partners                                                                                   6,678,500
  General partners                                                                                       6,800
                                                                              --------------------------------
                                                                                                     6,685,300
                                                                              --------------------------------
Total Liabilities and Partner's Equity                                         $                     6,798,000
                                                                              ================================
</TABLE>



                See accompanying notes to financial statements.

                                       2
<PAGE>

                           WINDSOR PARK PROPERTIES 6
                           -------------------------
                      (A California Limited Partnership)
                           STATEMENTS OF OPERATIONS
                           ------------------------
                                  (unaudited)

<TABLE>
<CAPTION>
                                                                                     Three Months Ended June 30,
                                                                        -----------------------------------------------------
                                                                                  1999                        1998
                                                                        -------------------------    ------------------------
REVENUES
--------
<S>                                                                     <C>                          <C>
Rent and utilities                                                       $                127,200     $               169,900
Equity in earnings of joint ventures and limited
partnerships                                                                               96,100                      63,400
Interest                                                                                    1,700                       3,800
Other                                                                                       6,700                       5,100
                                                                        -------------------------    ------------------------
                                                                                          231,700                     242,200
                                                                        -------------------------    ------------------------
COSTS AND
---------
EXPENSES
--------

Property operating                                                                         52,900                      82,300
Interest                                                                                        0                      31,700
Depreciation and amortization                                                              34,000                      45,200
General and administrative:
  Related parties                                                                           3,800                       7,900
  Other                                                                                    22,000                      15,400
                                                                        -------------------------    ------------------------
                                                                                          112,700                     182,500
                                                                        -------------------------    ------------------------
Net income                                                               $                119,000     $                59,700
                                                                        =========================    ========================
Net income  - general partners                                           $                  1,200     $                   600
                                                                        =========================    ========================
Net income - limited partners                                            $                117,800     $                59,100
                                                                        =========================    ========================
Basic and diluted earnings per limited partnership unit                  $                   0.41     $                  0.20
                                                                        =========================    ========================
</TABLE>



                See accompanying notes to financial statements.

                                       3
<PAGE>

                           WINDSOR PARK PROPERTIES 6
                           -------------------------
                      (A California Limited Partnership)
                           STATEMENTS OF OPERATIONS
                           ------------------------
                                  (unaudited)


<TABLE>
<CAPTION>
                                                                                 Six Months Ended June 30,
                                                                   -----------------------------------------------------
                                                                             1999                        1998
                                                                   -------------------------    ------------------------
REVENUES
--------
<S>                                                                <C>                          <C>
Rent and utilities                                                   $               254,400      $              334,700
Equity in earnings of joint ventures and limited
partnerships                                                                         202,700                     131,600
Interest                                                                               3,400                       8,400
Other                                                                                  9,500                       9,000
                                                                   -------------------------    ------------------------
                                                                                     470,000                     483,700
                                                                   -------------------------    ------------------------

COSTS AND EXPENSES
------------------

Property operating                                                                   107,000                     156,200
Interest                                                                                   0                      63,800
Depreciation and amortization                                                         66,900                      90,400
General and administrative:
  Related parties                                                                      8,400                      18,500
  Other                                                                               40,000                      33,600
                                                                   -------------------------    ------------------------
                                                                                     222,300                     362,500
                                                                   -------------------------    ------------------------
Net income                                                           $               247,700      $              121,200
                                                                   =========================    ========================
Net income  - general partners                                       $                 2,500      $                1,200
                                                                   =========================    ========================
Net income - limited partners                                        $               245,200      $              120,000
                                                                   =========================    ========================
Basic and diluted earnings per limited partnership  unit             $                  0.85      $                 0.41
                                                                   =========================    ========================
</TABLE>


                See accompanying notes to financial statements.

                                       4
<PAGE>

                           WINDSOR PARK PROPERTIES 6
                           -------------------------
                      (A California Limited Partnership)
                           STATEMENTS OF CASH FLOWS
                           ------------------------
                                  (unaudited)

<TABLE>
<CAPTION>
                                                                                        Six Months Ended June 30
                                                                         ------------------------------------------------------
                                                                                    1999                         1998
                                                                         ------------------------      ------------------------
Cash flows from operating activities:
<S>                                                                      <C>                           <C>
  Net income                                                               $              247,700        $              121,200
  Adjustments to reconcile net income to net cash provided
by operating activities:
    Depreciation and amortization                                                          66,900                        90,400
    Equity in earnings of joint ventures and limited
     partnerships                                                                        (202,700)                     (131,600)
    Joint ventures' and limited partnerships cash
     distributions                                                                        202,700                       131,600
    Amortization of deferred financing costs                                                    0                         5,300

    Changes in operating assets and liabilities:
      Other assets                                                                         (1,200)                       (5,000)
      Accounts payable                                                                          0                        (1,600)
      Due to General Partners and affiliates                                                4,300                       (21,700)
      Accrued expenses                                                                      2,100                        49,900
      Tenant deposits and other liabilities                                                  (100)                      (21,900)
                                                                         ------------------------      ------------------------
Net cash provided by operating activities                                                 319,700                       216,600
                                                                         ------------------------      ------------------------
Cash flows from investing activities:
  Joint ventures' and limited partnerships cash
    distributions                                                                         127,750                       231,100
  Increase in property held for investment                                                (17,500)                       (5,300)
  Investment in joint venture and limited partnerships                                       (850)                      (11,600)
                                                                         ------------------------      ------------------------
Net cash provided by investing activities                                                 109,400                       214,200
                                                                         ------------------------      ------------------------
Cash flows from financing activities:
  Cash distributions                                                                     (303,000)                     (296,700)
  Repurchase of limited partnership units                                                 (51,000)                      (68,100)
                                                                         ------------------------      ------------------------
Net cash used in financing activities                                                    (354,000)                     (364,800)
                                                                         ------------------------      ------------------------
Net decrease in cash and cash equivalents                                                  75,100                        66,000

Cash and cash equivalents at beginning of period                                          265,900                       359,300
                                                                         ------------------------      ------------------------
Cash and cash equivalents at end of period                                 $              341,000        $              425,300
                                                                         ========================      ========================
</TABLE>



                See accompanying notes to financial statements.

                                       5
<PAGE>

                           WINDSOR PARK PROPERTIES 6
                           -------------------------
                      (A California Limited Partnership)
                         NOTES TO FINANCIAL STATEMENTS
                         -----------------------------


NOTE 1.  THE PARTNERSHIP
         ----------------

Windsor Park Properties 6, A California Limited Partnership (the "Partnership"),
was formed in June 1988 for the purpose of acquiring and holding existing
manufactured home communities for investment.  The General Partners of the
Partnership are The Windsor Corporation ("TWC"), a California corporation, and
John A. Coseo, Jr.  In September 1998, Chateau Communities, Inc. a publicly held
real estate investment trust, ("Chateau"),  purchased 100 percent of the shares
of The Windsor Corporation.

The Partnership was funded through a public offering of 300,000 limited
partnership units at $100 per unit which commenced in September 1988 and
terminated in June 1990.  The Partnership term is set to expire in December
1999; however, the Partnership may either be dissolved earlier or extended under
certain circumstances.  The Partnership may be extended at the recommendation of
the General Partners with approval of a majority of the Limited Partners.

On November 1, 1998, the General Partners completed the sale of Circle K to an
unaffiliated third party for a purchase price of approximately $1.2 million in
which the proceeds were used to payoff the Partnership's outstanding mortgage
debt.

The General Partners are currently exploring possible strategic alternatives for
the Partnership with a view towards providing Limited Partners with the
opportunity to achieve liquidity in their investment.  There can, however, be no
assurances that any such strategic alternative will be consummated or that the
Partnership will not continue in its current form until the end of its stated
term.

NOTE 2.  BASIS OF PRESENTATION
         ---------------------

The balance sheet at June 30, 1999 and the related statements of operations for
the three and six months ended June 30, 1999 and 1998 and the statements of cash
flows for the six months ended June 30, 1999 and 1998 are unaudited. However, in
the opinion of the General Partners, they contain all adjustments, of a normal
recurring nature, necessary for a fair presentation of such financial
statements.  Interim results are not necessarily indicative of results for a
full year.

The financial statements and notes are presented as permitted by Form 10-QSB and
do not contain certain information included in the Partnership's annual
financial statements and notes on Form 10-KSB/A for the year ended December 31,
1998.

                                       6
<PAGE>

NOTE 3.  INVESTMENTS IN JOINT VENTURES AND LIMITED PARTNERSHIPS
         ------------------------------------------------------

The Partnership's investments in joint ventures and limited partnerships consist
of interests in five manufactured home communities.  The combined condensed
results of operations of these properties for the six months ended June 30, 1999
and 1998 are as follows:


<TABLE>
<CAPTION>

                                                  1999                       1998
                                        ----------------------      ---------------------
 <S>                                  <C>                         <C>
   Total revenues                      $             2,956,600     $            2,810,500
   Expenses:
    Property operating                               1,326,700                  1,300,700
    Interest                                           690,000                    742,800
    Depreciation                                       448,200                    435,100
    General and administrative                           6,000                     10,200
                                     -------------------------   ------------------------
                                                     2,470,900                  2,488,800
                                     -------------------------   ------------------------
   Net income                          $               485,700     $              321,700
                                     =========================   ========================
</TABLE>

NOTE 4.  BASIC AND DILUTED EARNINGS PER LIMITED PARTNERSHIP UNIT
         -------------------------------------------------------

Basic and diluted earnings per limited partnership unit is calculated based on
the weighted average number of limited partnership units outstanding during the
period and the net income allocated to the Limited Partners.  The weighted
average number of limited partnership units outstanding during the three and six
months ended June 30, 1999 and 1998 was 288,094 and 288,626 respectively; and
291,953 and 292,217 for the three and six months ended June 30, 1998
respectively.

NOTE 5.  DISTRIBUTIONS TO LIMITED PARTNERS
         ---------------------------------

Distributions to Limited Partners in excess of net income allocated to Limited
Partners are considered a return of capital.  A breakdown of cash distributions
to Limited Partners for the six months ended June 30, 1999 and 1998 follows:

<TABLE>
<CAPTION>
                                                    1999                                                1998
                                 ----------------------------------------------      ----------------------------------------------
                                                                         Per                                                 Per
                                       Amount                            Unit              Amount                            Unit
                                       ------                            ----              ------                            ----
<S>                                <C>                                  <C>            <C>                                  <C>
Net income
 - Limited Partners                $               245,200            $    0.85        $               120,000        $        0.41
Return of capital                                   54,800                  .19                        180,000                 0.62
                                 -------------------------      ---------------      -------------------------      ---------------
                                   $               300,000            $    1.04        $               300,000        $        1.03
                                 =========================      ===============      =========================      ===============
</TABLE>

                                       7
<PAGE>

Item 2.
-------

               Management's Discussion and Analysis of Financial
                      Condition and Results of Operations


Three months ended June 30, 1999 as compared to three months ended June 30, 1998
--------------------------------------------------------------------------------

The following discussion should be read in conjunction with the financial
statements and Notes thereto included elsewhere in this Form 10-QSB/A.

Results of Operations
---------------------

The results of operations for the three months ended June 30, 1999 and 1998 are
not directly comparable due to the sale of Circle K in November 1998.  The
Partnership realized net income of $119,000 and $59,700 for the three months
ended June 30, 1999 and 1998, respectively.  Net income per limited partnership
unit was $0.41 in 1999 and $0.20 in 1998.

Rent and utilities revenues decreased from $169,900 in 1998 to $127,200 in 1999,
due mainly to the sale of Circle K in November, 1998.

Equity in earnings of joint ventures and limited partnerships represents the
Partnership's share of the net income of five manufactured home communities.
Equity in earnings of joint ventures and limited partnerships increased from
$63,400 in 1998 to $96,100 in 1999 due to rental rate increases at the five
communities.

Interest income decreased from $3,800 in 1998 to $1,700 in 1999 due mainly to
lower cash balances maintained by the Partnership.

Property operating expenses decreased from $82,300 in 1998 to $52,900 in 1999
due mainly to the sale of Circle K in November, 1998.

Interest expense decreased from $31,700 in 1998 to $0 in 1999 due to the sale of
Circle K and subsequent repayment of the mortgage note payable.

Six months ended June 30, 1999 as compared to six months ended June 30, 1998
----------------------------------------------------------------------------

Results of Operations
---------------------

The results of operations for the six months ended June 30, 1999 and 1998 are
not directly comparable due to the sale of Circle K in November 1998.  The
Partnership realized net income of $247,700 and $121,200 for the six months
ended June 30, 1999 and 1998, respectively.  Net income per limited partnership
unit was $0.85 in 1999 and $0.41 in 1998.

Rent and utilities revenues decreased from $334,700 in 1998 to $254,400 in 1999,
due mainly to the sale of Circle K in November, 1998.

Equity in earnings of joint ventures and limited partnerships represents the
Partnership's share of the net income of five manufactured home communities.
Equity in earnings of joint ventures and limited partnerships increased from
$131,600 in 1998 to $202,700 in 1999 due to rental rate increases at the five
communities.

                                       8
<PAGE>

Interest income decreased from $8,400 in 1998 to $3,400 in 1999 due mainly to
lower cash balances maintained by the Partnership.

Property operating expenses decreased from $156,200 in 1998 to $107,000 in 1999
due mainly to the sale of Circle K in November, 1998.

Interest expense decreased from $63,800 in 1998 to $0 in 1999 due to the sale of
Circle K and subsequent repayment of the mortgage note payable.

Liquidity and Capital Resources
-------------------------------

The Partnership's primary sources of liquidity during the six months ended June
30, 1999 were its cash flow generated from the operation of its communities and
distributions from investments in joint ventures and limited partnerships. Net
cash provided by operating activities was $319,700 for the six months ended June
30, 1999.  At June 30, 1999, the Partnership's cash amounted to $341,000.

The Partnership's primary use of cash during the same period was for cash
distributions to partners.  Cash distributions to partners totaled $303,000 for
the six months ended June 30, 1999.

The Partnership's principal long-term liquidity requirement will be the
repayment of principal on its proportionate share of outstanding joint venture
mortgage debt. At June 30, 1999, the Partnership's proportionate share of joint
venture and limited partnership debt was $6,325,000, consisting entirely of
variable rate debt.  The average rate of interest on the variable rate debt was
8.3% at June 30, 1999.

The future sources of liquidity for the Partnership will be provided from
property operations, cash reserves, and ultimately from the sale of communities
and investments in joint ventures and limited partnerships. The Partnership
expects to meet its short-term liquidity requirements, including capital
expenditures, administration expenses, and distributions to partners, from cash
flow provided from property operations and distributions from investments in
joint ventures and limited partnerships.  The Partnership expects to meet its
long-term liquidity requirement through the sale of its communities and
investments in joint ventures and limited partnerships, and cash reserves.

Inflation
---------

All of the leases or terms of tenants' occupancies at the properties allow for
at least annual rental adjustments.  In addition, all of the leases are month-
to-month and enable the Partnership to seek market rentals upon reletting the
sites.  Such leases generally minimize the risk to the Partnership of any
adverse effect of inflation.

Year 2000 Compliance
--------------------

The General Partners have assessed the impact of the year 2000 issue on its
reporting systems and operations.  The year 2000 issue exists because many
computer systems and applications abbreviate dates by eliminating the first two
digits of the year, assuming that these two digits are always "19".  As a
result, date-sensitive computer programs may recognize a date using "00" as the
year 1900 rather than the year 2000.  Unless corrected, the potential exists for
computer system failures or incorrect processing of financial and operational
information, which could disrupt operations.

Substantially all of the computer systems and applications and operating systems
in use in use by the Windsor Corporation and the properties have been, or are in
the process of being upgraded and modified.  The Partnership is of the opinion
that, in connection with those upgrades and modifications, it has addressed
applicable year 2000 issues as they might affect the computer systems and
applications

                                       9
<PAGE>

located in the Partnership's offices and properties. The Partnership anticipates
that implementation of solutions to any year 2000 issue which it may discover
will require the expenditure of sums which the Partnership does not expect to be
material.

The Partnership is exposed to the risk that one or more of its vendors or
service providers may experience year 2000 problems which impact the ability of
such vendor or service provider to provide goods and services.  Due to the
availability of alternative suppliers, this is not considered as significant a
risk with respect to the suppliers of goods.  The disruption of certain
services, however, such as utilities, could, depending upon the extent of the
disruption, have a material adverse impact on the Partnership's operations.  To
date, the Partnership is not aware of any vendor or service provider year 2000
issue that management believes would have a material adverse impact on the
Partnership's operations.  The Partnership, however, has no means of ensuring
that its vendors or service providers will be year 2000 ready.  The inability of
vendors or service providers to complete the year 2000 resolution process in a
timely fashion could have an adverse impact on the Partnership and the effect of
non-compliance by vendors or service providers is not determinable at this time.
Residents who pay rent to the Partnership do not pose year 2000 problems for the
Partnership given the type and nature of the Partnership's properties and
residents.

Widespread disruptions in the national or international economy, including
disruptions affecting the financial markets, resulting from year 2000 issues, or
in certain industries, such as commercial or investment banks, could also have
an adverse impact on the Partnership.  The likelihood and effect of such
disruptions is not determinable at this time.

Management expects to have all systems appropriately modified before any
significant processing malfunctions could occur and does not expect the year
2000 issue will materially impact the financial condition or operations of the
Partnership

                                       10
<PAGE>

PART II
-------

Item 6.  EXHIBITS AND REPORTS ON FORM 8-K
         --------------------------------

         a) Exhibits and Index of Exhibits

               (3)    Certificate and Agreement of Limited Partnership filed as
                      Exhibit A to Registration Statement No. 33-23183 and
                      incorporated herein by reference.

               (27)   Financial Data Schedule

         b) Reports on Form 8-K

               None

                                       11
<PAGE>

                                   SIGNATURE



In accordance with the requirements of the Exchange Act, the registrant caused
this report to be signed on its behalf by the undersigned, thereunto duly
authorized.


                               WINDSOR PARK PROPERTIES 6,
                               A California Limited Partnership

                               By:  The Windsor Corporation, its General Partner


                               By /s/Steven G.Waite
                                  -----------------
                                  STEVEN G. WAITE
                                  President



Date:  February 3, 2000

                                       12