<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     March 31, 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>
<S>                                                               <C>
                         California                                             33-0299846
--------------------------------------------------------------    --------------------------------
(State or other jurisdiction of incorporation or organization)    (IRS Employer Identification No.)
</TABLE>

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


                                (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

<TABLE>
<CAPTION>
                                    PART I
                                    ------

                                                                      Page
                                                                      ----
<S>                                                                   <C>
Item 1.   Financial Statements                                         2

Item 2.   Management's Discussion and Analysis of Financial            7
          Condition and Results of Operations


                                    PART II
                                    -------


Item 6.   Exhibits and Reports on Form 8-K                             9


          SIGNATURE                                                   10
</TABLE>
<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>
                                                                    March 31, 1999
                                                                    --------------
<S>                                                                 <C>
ASSETS
------

Property held for investment:
  Land                                                              $     325,000
  Buildings and improvements                                            2,455,700
  Fixtures and equipment                                                   37,000
                                                                    -------------
                                                                        2,817,700
Less accumulated depreciation                                          (1,182,500)
                                                                    -------------
                                                                        1,635,200

Investments in joint ventures and limited partnerships                  4,955,900
Cash and cash equivalents                                                 143,000
Other assets                                                                3,800
                                                                    -------------

Total Assets                                                        $   6,737,900
                                                                    =============


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

Liabilities:
  Accrued expenses                                                  $     101,400
  Due to General Partner and affiliates                                    22,300
  Tenant deposits and other liabilities                                    11,200
                                                                    -------------

Total Liabilities                                                         134,900
                                                                    -------------

Partners' equity:
  Limited partners                                                      6,597,400
  General partners                                                          5,600
                                                                    -------------

                                                                        6,603,000
                                                                    -------------
Total Liabilities and Partner's Equity                              $   6,737,900
                                                                    =============
</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 March 31,
                                                                        ----------------------------
                                                                           1999              1998
                                                                        -----------      -----------
<S>                                                                     <C>              <C>
REVENUES
--------

Rent and utilities                                                      $   127,200      $   164,800
Equity in earnings of joint ventures and limited partnerships               106,600           68,200

Interest                                                                      1,700            4,700
Other                                                                         2,700            3,900
                                                                        -----------      -----------

                                                                            238,200          241,600
                                                                        -----------      -----------

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

Property operating                                                           54,100           74,000
Interest                                                                          0           32,100
Depreciation and amortization                                                32,900           45,200
General and administrative:
  Related parties                                                             4,600           10,600
  Other                                                                      17,900           18,200
                                                                        -----------      -----------

                                                                            109,500          180,100
                                                                        -----------      -----------

Net income                                                              $   128,700      $    61,500
                                                                        ===========      ===========

Net income  - general partners                                          $     1,300      $       600
                                                                        ===========      ===========

Net income - limited partners                                           $   127,400      $    60,900
                                                                        ===========      ===========

Basic and Dilutive earnings per limited partnership unit                $      0.44      $      0.21
                                                                        ===========      ===========
</TABLE>

                See accompanying notes to financial statements.

                                      -3-
<PAGE>

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

<TABLE>
<CAPTION>
                                                             Three Months Ended March 31,
                                                             -----------------------------
                                                                 1999               1998
                                                             -----------        ----------
<S>                                                          <C>                <C>
Cash flows from operating activities:
  Net income                                                 $   128,700        $   61,500
  Adjustments to reconcile net income to net
  cash provided by operating activities:
    Depreciation and amortization                                 32,900            45,200
    Equity in earnings of joint ventures and limited
     partnerships                                               (106,600)          (68,200)

    Joint ventures' and limited partnerships cash
     distributions                                               106,600            68,200

    Amortization of deferred financing costs                           0             2,700

    Changes in operating assets and liabilities:
      Other assets                                                 2,300             5,000
      Accounts payable                                            (1,400)           (4,400)
      Due to General Partners and affiliates                      12,100             5,300
      Accrued expenses                                            17,900            34,000
      Tenant deposits and other liabilities                         (100)          (20,600)

Net cash provided by operating activities                        192,400           128,700
                                                             -----------        ----------

Cash flows from investing activities:
  Joint ventures'  and limited partnerships cash
   distributions                                                  10,600           156,300

  Increase in property held for investment                        (8,500)           (1,100)
  Investment in joint venture and partnerships                      (100)                0
                                                             -----------        ----------

Net cash provided by investing activities                          2,000           155,200
                                                             -----------        ----------

Cash flows from financing activities:
  Cash distributions                                            (303,000)          296,700)
  Repurchase of limited partnership units                        (14,300)          (14,200)
                                                             -----------        ----------

Net cash used in financing activities                           (317,300)          310,900)
                                                             -----------        ----------

Net decrease in cash and cash equivalents                       (122,900)          (27,000)

Cash and cash equivalents at beginning of period                 265,900           359,300
                                                             -----------        ----------

Cash and cash equivalents at end of period                   $   143,000        $  332,300
                                                             ===========        ==========
</TABLE>

                See accompanying notes to financial statements.

                                      -4-
<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 March 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 March 31, 1999 and the related statements of operations for
the three months ended March 31, 1999 and 1998 and the statements of cash flows
for the three months ended March 31, 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.

                                      -5-
<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 three months ended March 31,
1999 and 1998 are as follows:


<TABLE>
<CAPTION>
                                           1999               1998
   <S>                                 <C>             <C>
Total revenues                         $ 1,478,900     $  1,401,300
Expenses:
  Property operating                       647,600          639,900
  Interest                                 346,500          373,300
  Depreciation                             223,200          217,500
  General and administrative                 1,700            2,900
                                       -----------     ------------

                                         1,219,000        1,233,600
                                       -----------     ------------

Net income                             $   259,900     $    167,700
                                       ===========     ============
</TABLE>

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

Basic and dilutive 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 months
ended March 31, 1999 and 1998 was 289,059 and 292,852 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 three months ended March 31, 1999 and 1998 follows:

<TABLE>
<CAPTION>
                                        1999                              1998
                              -------------------------       ----------------------------

                                                Per                                 Per
                                Amount          Unit            Amount              Unit
                                ------          ----            ------              ----
<S>                           <C>               <C>           <C>                 <C>
Net income
 - limited partners           $   127,400       $  0.44       $     60,900        $   0.20
Return of capital                 172,600          0.60            239,100            0.82
                              -----------       -------       ------------        --------

                              $   300,000       $  1.04       $    300,000        $   1.02
                              ===========       =======       ============        ========
</TABLE>

                                      -6-
<PAGE>

Item 2.
-------

               MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL
               ------------------------------------------------
                      CONDITION AND RESULTS OF OPERATIONS
                      -----------------------------------

Three months ended March 31, 1999 as compared to three months ended March 31,
-----------------------------------------------------------------------------
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 March 31, 1999 and 1998 are
not directly comparable due to the sale of Circle K in November 1998.  The
Partnership realized net income of $128,700 and $61,500 for the three months
ended March 31, 1999 and 1998, respectively.  Net income per limited partnership
unit was $0.44 in 1999 and $0.21 in 1998.

Rent and utilities revenues decreased from $164,800 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
$68,200 in 1998 to $106,600 in 1999 due to rental rate increases at the five
communities.

Interest income decreased from $4,700 in 1998 to $1,700 in 1999 due mainly to
lower cash balances maintained by the Partnership.

Property operating expenses decreased from $74,000 in 1998 to $54,100 in 1999
due mainly to the sale of Circle K in November, 1998.

Interest expense decreased from $32,100 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 three months ended
March 31, 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 $192,400 for the
three months ended March 31, 1999.  At March 31, 1999, the Partnership's cash
amounted to $143,000.

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 three months ended March 31, 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 March 31, 1999, the Partnership's proportionate share of joint
venture and limited partnership debt, was $6,331,200, consisting entirely of
variable rate debt.  The average rate of interest on the variable rate debt was
8.3% at March 31, 1999.

                                      -7-
<PAGE>


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 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

                                      -8-
<PAGE>

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

                                      -9-
<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

                                      -10-
<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

                                      -11-