737 MAX production halt and a significant decline in the price of oil followed soon after.
Last, but certainly not least, COVID-19 significantly affected end markets in all regions in the second half of our fiscal year, especially in Q4.
COVID-19 protocols we successfully implemented continue to allow us to operate safely and serve customers globally.
In Q4, the Company reported an organic sales decline of 33% on top of the 2% decline in the prior year quarter, which is the worst quarterly organic decline since the Great Recession in 2008.
All segments reported negative organic growth for the quarter with Industrial declining by 36%, WIDIA 32%, and Infrastructure at 29% compared to negative 4% and 3% for Industrial and WIDIA and infrastructure at 1% growth in the prior year quarter.
Also, all regions were negative with the Americas posting a 39% decline, EMEA 34%, and Asia Pacific 24%.
Adjusted operating expenses declined 18% reflecting our cost control measures.
Adjusted EBITDA margin for the quarter was 17.7%, a decrease of 330 basis points from 21% in the prior year.
Turning to Slide 4, due to COVID-19, it remains difficult to forecast how our customers as well as our end-markets will be affected.
As a result, we will not be providing an annual outlook for fiscal year '21.
But as you know, the Company typically sees, on average, an approximately 10% seasonal decline in revenues from Q4 to Q1.
Capital spending will be significantly reduced by over $100 million to be in the range of $110 million to $130 million for the full year.
The benefits of these investments will continue to increase in fiscal year '21 bringing savings since inception to approximately $180 million at fiscal year-end, including total Company headcount reduced by approximately 20% and a rationalized footprint with six fewer plants and more production moving to lower-cost countries.
We expect that this approach will open up a 40% increase in served market opportunity while offering better service and tooling options to our customers.
For the quarter, sales declined 37% year-over-year, in line with the decline seen in April or negative 33% on organic basis to $379 million.
Foreign currency had a negative effect of 2% and our divestiture contributed another negative 2%.
Adjusted gross profit margin of 27.7% was down 790 basis points year-over-year.
The year-over-year performance was primarily due to the effect of lower volumes and associated absorption, partially offset by cost control actions including furloughs, increasing benefits from simplification/modernization and the positive effect of raw materials, which amounted to approximately 140 basis points.
Adjusted operating expenses of $68 million were down 41% year-over-year and decreased to 18% as a percentage of sales.
EBITDA margin was 17.7%, down 330 basis points from the previous-year quarter.
Taken together, adjusted operating margin of 8.8% was down 700 basis points year-over-year.
The adjusted effective tax rate in the quarter was significantly higher at 51.2% due to the combined effects of geographical mix changes in our taxable income as well as the magnified effect of GILTI on the effective tax rate as we finalized actual full-year taxable income versus estimates.
It's worth noting that our adjusted effective tax rate for the full year was approximately 33%.
We reported a GAAP earnings per share loss of $0.11 versus earnings per share of $0.74 in the prior-year period, which reflects the reduced volume and higher tax rate, partially offset by our cost control actions coupled with restructuring items.
On an adjusted basis, earnings per share was $0.15 per share in the quarter versus $0.84 in the prior year.
Effective operations this quarter amounted to negative $0.68.
This compares to negative $0.08 in the prior year period and negative $0.39 in the third quarter.
The largest factor contributing to the $0.68 was the effect of significantly lower volume and associated under-absorption.
This was partially offset by cost control actions, including lower variable compensation as well as positive raw materials of $0.08.
Simplification/modernization contributed $0.14 in the quarter on top of the $0.10 in the prior year.
This brings the total FY '20 simplification/modernization savings to $0.46.
As Chris mentioned, our expectations for FY '21 is that the simplification/modernization benefits will be in the range of $0.80, driven by actions already taken or announced.
In terms of benefits from our restructuring program, the savings from our FY '20 restructuring actions delivered approximately $33 million in run rate annualized savings at the end of FY '20.
FY '21 restructuring actions are expected to contribute an additional $65 million to $75 million of annualized run rate savings by the end of FY '21.
Slide 9 through 11 details the performance of our segments this quarter.
Industrial sales in Q4 declined 36% organically on top of a 4% decline in the prior year period.
All regions posted year-over-year sales declines with the largest decline in the Americas at negative 40% followed by EMEA at 38% and Asia-Pacific at 27%.
From an end market perspective, the weakness in demand remains broad based, with significant declines in transportation and general engineering down 45% and 32% respectively.
Adjusted operating margin came in at 7.7% compared to 18.3% in the prior year quarter.
The decrease was primarily driven by the decline in volume and associated under-absorption, partially offset by reduced variable compensation and other cost control actions, increased simplification/modernization benefits and a 90 basis point benefit from raw materials.
On a sequential basis, adjusted operating margin decreased 540 basis points as lower volumes were partially offset by aggressive cost control actions and lower variable compensation.
Sales declined 32% on top of a negative 3% in the prior year period.
Regionally, the largest decline this quarter was in Asia Pacific down 41%, the Americas 31% and EMEA 28%.
Adjusted operating margin for the quarter was negative 2.9% due to volume declines, partially offset by lower variable compensation and other cost control actions, a raw material benefit of 220 basis points, and increased simplification/modernization benefits.
Organic sales declined 29% versus positive 1% in the prior year period.
Other items that negatively affected Infrastructure sales included a divestiture of 4%, FX of 2% and fewer business days of 1%.
Regionally, the largest decline was in the Americas at 39%, then EMEA at 22%, and Asia-Pacific at 14%.
By end market, these results were primarily driven by energy, which was down 47% year-over-year, given the extreme drop in oil prices and the corresponding decline in the U.S. land-only rig count.
General Engineering and Earthworks were down 31% and 17% respectively.
Adjusted operating margin of 12.7% remained relatively stable sequentially, but decreased 280 basis points from the prior year margin of 15.5%.
This decrease was mainly driven by lower volumes and associated under-absorption, partially offset by reduced variable compensation and other cost control actions, favorable raw materials that contributed 200 basis points and benefits from simplification/modernization.
Before I review the numbers, like I did last quarter, I would like to emphasize that we view liquidity as extremely important, particularly in these uncertain times.
Our current debt maturity profile is made up of two $300 million notes maturing in February of 2022 and June of 2028 as well as a U.S. $700 million revolver that matures in June of 2023.
At fiscal year-end, we had combined cash and revolver availability of approximately $800 million.
Primary working capital decreased both sequentially and year-over-year to $596 million.
On a percentage of sales basis, it increased to 35.4%, a reflection of the significant decline in sales in the quarter.
Net capital expenditures were $38 million, a decrease of approximately $20 million from the prior year, bringing the total capital spend for the year to $242 million as expected.
Our fourth quarter free operating cash flow was $39 million and represents a year-over-year decline, reflecting lower income due to volume and increased cash restructuring cost.
Total free operating cash flow for the full year was negative $18 million.
In addition, we paid the dividend of $17 million in the quarter.
As I mentioned earlier, we expect increased simplification/modernization benefits of approximately $80 million in FY '21.
As we think about the temporary cost control actions that we've announced in June, they will generate a savings of $10 million to $15 million per quarter in the first half of FY '21 relative to the first half of FY '20.
Depreciation and amortization will step up to a range of approximately $130 million to $140 million compared to approximately $120 million in FY '20.
We currently expect our full year tax rate in FY '21 to be similar to the 33% adjusted effective tax rate we saw in FY '20, but it could fluctuate significantly in any given quarter depending on the effects of geographical mix and the sensitivity to lower pre-tax income.
Regardless of the effective tax rate, we expect cash taxes in FY '21 to be approximately $10 million less than the $37 million paid in FY '20.
In regard to free operating cash flow, capital expenditures will be significantly lower versus last year, as Chris mentioned, by approximately $120 million.
We currently expect cash restructuring charges to be $25 million to $35 million higher in FY '21 with the majority of this increase in the first half.
Finally, we'll continue to pursue our strategic growth initiatives so that we can position the Company for profitable growth and share gain as end markets recover and to achieve our adjusted EBITDA profitability target when sales reach a top line range of $2.5 billion to $2.6 billion.

Summary:
Last, but certainly not least, COVID-19 significantly affected end markets in all regions in the second half of our fiscal year, especially in Q4.
COVID-19 protocols we successfully implemented continue to allow us to operate safely and serve customers globally.
Turning to Slide 4, due to COVID-19, it remains difficult to forecast how our customers as well as our end-markets will be affected.
As a result, we will not be providing an annual outlook for fiscal year '21.
Capital spending will be significantly reduced by over $100 million to be in the range of $110 million to $130 million for the full year.
For the quarter, sales declined 37% year-over-year, in line with the decline seen in April or negative 33% on organic basis to $379 million.
We reported a GAAP earnings per share loss of $0.11 versus earnings per share of $0.74 in the prior-year period, which reflects the reduced volume and higher tax rate, partially offset by our cost control actions coupled with restructuring items.
On an adjusted basis, earnings per share was $0.15 per share in the quarter versus $0.84 in the prior year.
Before I review the numbers, like I did last quarter, I would like to emphasize that we view liquidity as extremely important, particularly in these uncertain times.