SC 13D/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 3)*

STR HOLDINGS, INC.

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

78478V100

(CUSIP Number)

Red Mountain Capital Partners LLC

Attn: Willem Mesdag

10100 Santa Monica Boulevard, Suite 925

Los Angeles, California 90067

Telephone (310) 432-0200

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

February 6, 2012

(Date of Event Which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box.  ¨

Note. Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 78478V100 SCHEDULE 13D/A         PAGE 2 OF 9 PAGES

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Red Mountain Capital Partners LLC                             73-1726370
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  x        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS*                                                                                   AF (See Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY   OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     4,110,011 shares (See Item 5)
		8	SHARED VOTING POWER     None (See Item 5)
		9	SOLE DISPOSITIVE POWER     4,110,011 shares (See Item 5)
		10	SHARED DISPOSITIVE POWER     None (See Item 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,110,011 shares (See Item 5)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*			¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     9.9% (See Item 5)
14	TYPE OF REPORTING PERSON *     OO – Limited Liability Company

* See Instructions

CUSIP No. 78478V100 SCHEDULE 13D/A         PAGE 3 OF 9 PAGES

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Red Mountain Capital Partners II, L.P. 20-4117535
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  x        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS*                                                                                   WC (See Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY   OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     4,110,011 shares (See Item 5)
		8	SHARED VOTING POWER     None (See Item 5)
		9	SOLE DISPOSITIVE POWER     4,110,011 shares (See Item 5)
		10	SHARED DISPOSITIVE POWER     None (See Item 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,110,011 shares (See Item 5)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*			¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     9.9% (See Item 5)
14	TYPE OF REPORTING PERSON *     PN – Limited Partnership

* See Instructions

CUSIP No. 78478V100 SCHEDULE 13D/A         PAGE 4 OF 9 PAGES

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) RMCP GP LLC 20-4442412
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  x        (b)  ¨
3	SEC USE ONLY
4	SOURCE OF FUNDS*                                                                                   AF (See Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY   OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     4,110,011 shares (See Item 5)
		8	SHARED VOTING POWER     None (See Item 5)
		9	SOLE DISPOSITIVE POWER     4,110,011 shares (See Item 5)
		10	SHARED DISPOSITIVE POWER     None (See Item 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,110,011 shares (See Item 5)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*			¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     9.9% (See Item 5)
14	TYPE OF REPORTING PERSON *     OO – Limited Liability Company

* See Instructions

CUSIP No. 78478V100 SCHEDULE 13D/A         PAGE 5 OF 9 PAGES

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Red Mountain Capital Management, Inc.                             13-4057186
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	SOURCE OF FUNDS*                                                                                   AF (See Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     Delaware
NUMBER OF SHARES BENEFICIALLY   OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     4,110,011 shares (See Item 5)
		8	SHARED VOTING POWER     None (See Item 5)
		9	SOLE DISPOSITIVE POWER     4,110,011 shares (See Item 5)
		10	SHARED DISPOSITIVE POWER     None (See Item 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,110,011 shares (See Item 5)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*			¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     9.9% (See Item 5)
14	TYPE OF REPORTING PERSON *     CO – Corporation

* See Instructions

CUSIP No. 78478V100 SCHEDULE 13D/A         PAGE 6 OF 9 PAGES

1	NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) Willem Mesdag
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a)  ¨        (b)  x
3	SEC USE ONLY
4	SOURCE OF FUNDS*                                                                                   AF (See Item 3)
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)			¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION     U.S. Citizen
NUMBER OF SHARES BENEFICIALLY   OWNED BY EACH REPORTING PERSON WITH		7	SOLE VOTING POWER     4,110,011 shares (See Item 5)
		8	SHARED VOTING POWER     None (See Item 5)
		9	SOLE DISPOSITIVE POWER     4,110,011 shares (See Item 5)
		10	SHARED DISPOSITIVE POWER     None (See Item 5)
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON     4,110,011 shares (See Item 5)
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES*			¨
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)     9.9% (See Item 5)
14	TYPE OF REPORTING PERSON *     IN – Individual

* See Instructions

CUSIP No. 78478V100 SCHEDULE 13D/A         PAGE 7 OF 9 PAGES

This Amendment No. 3 amends and supplements the Schedule 13D filed with the Securities and Exchange Commission (the “SEC”) on August 15, 2011, as amended by Amendment No. 1 thereto, filed with the SEC on October 11, 2011, and Amendment No. 2 thereto, filed with the SEC on February 1, 2012 (together, this “Schedule 13D”), by (i) Red Mountain Capital Partners LLC, a Delaware limited liability company (“RMCP LLC”), (ii) Red Mountain Capital Partners II, L.P., a Delaware limited partnership (“RMCP II”), (iii) RMCP GP LLC, a Delaware limited liability company (“RMCP GP”), (iv) Red Mountain Capital Management, Inc., a Delaware corporation (“RMCM”), and (v) Willem Mesdag, a natural person and citizen of the United States of America, with respect to the common stock, par value $0.01 per share (the “Common Stock”), of STR Holdings, Inc., a Delaware corporation (“STRI”). RMCP LLC, RMCP II, RMCP GP, RMCM and Mr. Mesdag are sometimes collectively referred to herein as the “Reporting Persons.” The filing of any amendment to this Schedule 13D (including the filing of this Amendment No. 3) shall not be construed to be an admission by the Reporting Persons that a material change has occurred in the facts set forth in this Schedule 13D or that such amendment is required under Rule 13d-2 of the Securities Exchange Act of 1934, as amended.

ITEM 4. PURPOSE OF TRANSACTION

Item 4 of this Schedule 13D is hereby amended by adding the following:

On January 31, 2012, RMCP LLC sent a letter (the “Letter to Management”) to Dennis L. Jilot, the Executive Chairman of the Board of Directors of STRI, asking STRI to consider, among other things, the addition of J. Christopher Teets to STRI’s Board of Directors and the retirement of up to three directors appointed by DLJ Merchant Banking Partners. This summary of the Letter to Management is qualified entirely by reference to the full text of the Letter to Management, a copy of which was filed as Exhibit 2 to Amendment No. 2 to this Schedule 13D and is incorporated herein by reference.

On February 3, 2012, RMCP LLC received a letter (the “Management Response”) from Mr. Jilot, rejecting RMCP LLC’s suggestions in the Letter to Management. A copy of the Management Response is attached hereto as Exhibit 3. The Management Response is being furnished as an exhibit to this Schedule 13D solely for background purposes, and the Reporting Persons disclaim any responsibility for the accuracy of any statement made in the Management Response.

On February 6, 2012, RMCP LLC sent a letter (the “Second Letter to Management”) to Mr. Jilot in response to the Management Response. The Second Letter to Management, among other things, urged Mr. Jilot and STRI’s Board of Directors to reconsider their position regarding the addition of J. Christopher Teets to STRI’s Board of Directors. The foregoing description of the Second Letter to Management is qualified in its entirety by reference to the full text of the Second Letter to Management, a copy of which is attached hereto as Exhibit 4 and is incorporated herein by reference.

ITEM 7. MATERIAL TO BE FILED AS EXHIBITS

Item 7 of this Schedule 13D is hereby amended to include the following information:

Exhibit No.	Description of Exhibit
3	Management Response, dated as of February 3, 2012, sent by Dennis L. Jilot, Executive Chairman of the Board of STRI, to RMCP LLC (filed herewith).
4	Second Letter to Management, dated as of February 6, 2012, sent by RMCP LLC to Dennis L. Jilot, Executive Chairman of the Board of STRI (filed herewith).

CUSIP No. 78478V100 SCHEDULE 13D/A         PAGE 8 OF 9 PAGES

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: February 7, 2012

RED MOUNTAIN CAPITAL PARTNERS LLC
/s/ Willem Mesdag
By:	Willem Mesdag
Title:	Authorized Signatory
RED MOUNTAIN CAPITAL PARTNERS II, L.P.
By:	RMCP GP LLC, its general partner
	/s/ Willem Mesdag
	By:	Willem Mesdag
	Title:	Authorized Signatory
RMCP GP LLC
/s/ Willem Mesdag
By:	Willem Mesdag
Title:	Authorized Signatory
RED MOUNTAIN CAPITAL MANAGEMENT, INC.
/s/ Willem Mesdag
By:	Willem Mesdag
Title:	President
WILLEM MESDAG
/s/ Willem Mesdag

CUSIP No. 78478V100 SCHEDULE 13D/A         PAGE 9 OF 9 PAGES

EXHIBIT INDEX

Exhibit No.	Description of Exhibit
1	Joint Filing Agreement, dated as of August 15, 2011, by and among the Reporting Persons (incorporated by reference to Exhibit 1 to the Schedule 13D filed by the Reporting Persons with the SEC on August 15, 2011).
2	Letter to Management, dated as of January 31, 2012, sent by RMCP LLC to Dennis L. Jilot, Executive Chairman of the Board of STRI (incorporated by reference by Exhibit 2 to Amendment No. 2 to Schedule 13D filed by the Reporting Persons with the SEC on February 1, 2012).
3	Management Response, dated as of February 3, 2012, sent by Dennis L. Jilot, Executive Chairman of the Board of STRI, to RMCP LLC (filed herewith).
4	Second Letter to Management, dated as of February 6, 2012, sent by RMCP LLC to Dennis L. Jilot, Executive Chairman of the Board of STRI (filed herewith).

EX-3

Exhibit 3

1699 King St. — Suite 400

Enfield, CT. 06082

Phone: 860-758-7320 —

Fax: 860-758-7302

February 3, 2012

Mr. Willem Mesdag

Managing Partner

Red Mountain Capital Partners LLC

10100 Santa Monica Boulevard, Suite 925

Los Angeles, California 90067

Dear Will:

I received your letter dated January 31, 2012, and have shared it with the Board of Directors of STR Holdings, Inc. In light of the discussions that you have been having with me on behalf of the Board as well as with the Company’s management team over the past few months, we are disappointed that you decided to communicate with us in this fashion. As we have already discussed, we believe that the Company’s Board and management team have the skills, experience and diversity to address the challenges facing the Company and to look after the best interests of the Company and all of its stockholders.

As reflected in our updated guidance issued earlier today, the Company’s management team and the Board are acutely aware of the challenges facing us. These challenges are not unique to STR – they are challenges being faced by the entire solar energy supply chain. Our Board believes that we have the right team in place to address these challenges and to execute on the Company’s strategic plan. As noted in your letter, we have and will continue to focus on, among other things, inventory and receivables management and capacity utilization. We are protecting our future with prudent investments in capital equipment as well as in research and development. We welcome specific suggestions you may have with regard to the near or long-term actions mentioned in your letter.

As we have discussed, the Nominating and Corporate Governance Committee of the Board regularly evaluates the needs and challenges being faced by the Company as well as the background and experience of the Company’s directors and how the Board functions as a governing body. The Committee carefully considers whether the Company’s directors, as a group, have the background and experience necessary to, among other things, (i) provide oversight of the Company’s business, operations and strategic direction, (ii) consult with the Company’s management team, as appropriate, and (iii) look after the best interests of the Company and all of its stockholders.

The Committee (as well as the full Board) has carefully considered the concerns that you have raised about the Board and your request that we invite your partner, Christopher Teets, to join the Company’s Board. Given the current composition of the Board and Mr. Teets’ background as an investment banker and director of other companies not relevant to our business, we do not believe that having Mr. Teets join the Board would enhance the Board’s position to meet its responsibilities. The Committee will continue to regularly evaluate the composition of the Company’s Board and the skills and experience that are necessary for the Board to continue to discharge its duties to the Company and its stockholders – particularly in light of the challenges facing the Company.

Mr. Willem Mesdag

February 3, 2012

Page 2

In your justification to obtain a seat for your firm on the Company’s Board, you have inaccurately described its composition. You state that DLJ “dominates” the Board and controls the Compensation and Governance Committees. This is inaccurate. We strongly disagree with your assertion that any director formerly affiliated with DLJ is unable to provide an independent view. This is simply wrong. All of the Company’s directors (other than our CEO and me) are independent under the rules of the NYSE and the SEC, six of whom are qualified to serve on our Audit Committee. Therefore, and contrary to the statement in your letter, there are a sufficient number of independent directors to effectively rotate through each of the Company’s Board committees. In fact, Committee memberships were reassigned in July of last year and are reviewed annually.

Further, as part of the process of regularly reviewing the composition of the Board, in August 2010, two new independent directors with significant relevant CEO level solar and cleantech experience joined the Board. Just last month, one of the Company’s directors affiliated with DLJ resigned and was replaced by the long-time President of our solar business and newly elected CEO.

We strongly disagree with your concern that our Board does not have the necessary background, experience and diversity to protect the best interests of our stockholders. The Company’s directors are a diverse group of senior executives with different and complementary backgrounds, skills and relevant global experience. We believe that each of the directors has the attributes necessary to make a substantial contribution to the Board and to position the Board, as a group, to discharge its duties to the Company and its stockholders. Given his background and experience, especially in light of the executive level operating experience of our current directors, we do not agree that Mr. Teets would enhance the Board or add to its diversity. Further, as you know, I have previously shared with you that in light of the sale of our Quality Assurance division last September and the resulting contraction of the size and scope of our business, we are much more likely to reduce the size of our Board than we are to increase it.

We appreciate your input and, as has been the case, look forward to hearing your perspective and that of other stockholders. It is important that we continue to have a regular, open dialogue with our stockholders.

Very truly yours,

/s/ Dennis L. Jilot

Dennis L. Jilot

Executive Chairman

cc: Board of Directors, STR Holdings, Inc.

EX-4

Exhibit 4

February 6, 2012

SENT VIA FEDEX AND EMAIL

Dennis L. Jilot

Executive Chairman

STR Holdings, Inc.

1699 King Street, Suite 400

Enfield, CT 06082

Dear Den,

Thank you for your prompt response to my letter dated January 31, 2012. We are disappointed by your Board’s refusal to act on a constructive and value-added suggestion by one of STR’s major shareholders.

I would like to emphasize that we are asking you to invite Christopher Teets to join STR’s Board because he will provide a fresh shareholder perspective. As you know, we broadly support you and your management team, and have great respect for those directors you have recruited who have relevant industry expertise and experience. However, we are concerned that four STR directors are or have been affiliated with one major shareholder of the company, and have similar backgrounds and deep personal and professional relationships with each other. It is self-evident that Mr. Teets would add to the independence and diversity of the Board, and would enhance it with his successful public company board experience and his unique insights as another significant shareholder. We support your intention to reduce the size of the Board, and have outlined a clear path to do so.

On Friday, February 3^rd, you announced that STR’s Q4 2011 revenue would be $36.5 million, down 20% from your recent projection of $44-48 million, and that earnings per share would be a negative $0.02-0.04, down dramatically from your recent projection of a positive $0.09-0.12. In response, STR’s stock price declined by more than 20% — following a previous 60% decline from its high in November 2010. Clearly, these are uncertain times that call for fresh thinking.

We urge you and the Board to reconsider your position in advance of the deadline under STR’s bylaws for shareholder nomination of directors. As one of your largest shareholders, we strongly believe that a Board that includes Mr. Teets will be better able to address the challenges facing STR and to look after the best interests of the company and all of its shareholders.

Sincerely yours,

/s/ Willem Mesdag

Willem Mesdag

Managing Partner

10100 SANTA MONICA BOULEVARD, SUITE 925, LOS ANGELES, CA 90067 · MAIN 310-432-0200 · FAX 310-432-0201