UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO

§ 240.13d-2(a)

(Amendment No. 15)1

Adaptec, Inc.

(Name of Issuer)

Common Stock, par value $0.001

(Title of Class of Securities)

00651F108

(CUSIP Number)

Warren G. Lichtenstein

Steel Partners II, L.P.

590 Madison Avenue, 32nd Floor

New York, New York 10022

(212) 520-2300

(Name, Address and Telephone Number of Person

Authorized to Receive Notices and Communications)

October 22, 2009

(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 §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-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 § 240.13d-7 for other parties to whom copies are to be sent.

_______________

1              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. 00651F108

1	NAME OF REPORTING PERSON STEEL PARTNERS II, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o   (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS WC
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 - 0 -
	8	SHARED VOTING POWER 15,396,138
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 15,396,138
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 15,396,138
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.8%
14	TYPE OF REPORTING PERSON PN

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CUSIP NO. 00651F108

1	NAME OF REPORTING PERSON STEEL PARTNERS HOLDINGS L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o   (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 - 0 -
	8	SHARED VOTING POWER 15,396,138
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 15,396,138
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 15,396,138
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.8%
14	TYPE OF REPORTING PERSON PN

3

CUSIP NO. 00651F108

1	NAME OF REPORTING PERSON STEEL PARTNERS LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o   (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 - 0 -
	8	SHARED VOTING POWER 15,396,138
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 15,396,138
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 15,396,138
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.8%
14	TYPE OF REPORTING PERSON OO

4

CUSIP NO. 00651F108

1	NAME OF REPORTING PERSON STEEL PARTNERS II GP LLC
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o   (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 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 - 0 -
	8	SHARED VOTING POWER 15,396,138
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 15,396,138
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 15,396,138
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.8%
14	TYPE OF REPORTING PERSON OO

5

CUSIP NO. 00651F108

1	NAME OF REPORTING PERSON WARREN G. LICHTENSTEIN
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o   (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER - 0 -
	8	SHARED VOTING POWER 15,396,138
	9	SOLE DISPOSITIVE POWER - 0 -
	10	SHARED DISPOSITIVE POWER 15,396,138
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 15,396,138
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.8%
14	TYPE OF REPORTING PERSON IN

6

CUSIP NO. 00651F108

1	NAME OF REPORTING PERSON JACK L. HOWARD
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o   (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 18,750 *
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 18,750 *
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 18,750 *
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) LESS THAN 1%
14	TYPE OF REPORTING PERSON IN

* Represents 6,250 Shares underlying a Restricted Stock Award and 12,500 Shares underlying Non-Qualified Stock Options that are exercisable within 60 days of the date hereof.

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CUSIP NO. 00651F108

1	NAME OF REPORTING PERSON JOHN J. QUICKE
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) o   (b) o
3	SEC USE ONLY
4	SOURCE OF FUNDS OO
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEM 2(d) OR 2(e)		¨
6	CITIZENSHIP OR PLACE OF ORGANIZATION USA
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH	7	SOLE VOTING POWER 18,750 *
	8	SHARED VOTING POWER - 0 -
	9	SOLE DISPOSITIVE POWER 18,750 *
	10	SHARED DISPOSITIVE POWER - 0 -
11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 18,750 *
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES		o
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) LESS THAN 1%
14	TYPE OF REPORTING PERSON IN

* Represents 6,250 Shares underlying a Restricted Stock Award and 12,500 Shares underlying Non-Qualified Stock Options that are exercisable within 60 days of the date hereof.

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CUSIP NO. 00651F108

The following constitutes Amendment No. 15 to the Schedule 13D filed by the undersigned (“Amendment No. 15”).  This Amendment No. 15 amends the Schedule 13D as specifically set forth.

Item 3. Source and Amount of Funds or Other Consideration.

Item 3 is hereby amended and restated to read as follows:

The aggregate purchase price of the 15,396,138 Shares owned by Steel Partners II is approximately $51,150,306, including brokerage commissions.  The Shares owned by Steel Partners II were acquired with partnership funds.

The Shares beneficially owned by Messrs. Howard and Quicke were awarded to them in their capacities as directors of the Issuer.

Steel Partners II effects purchases of securities primarily through margin accounts maintained for it with prime brokers, which may extend margin credit to it as and when required to open or carry positions in the margin accounts, subject to applicable federal margin regulations, stock exchange rules and the prime brokers’ credit policies.  In such instances, the positions held in the margin accounts are pledged as collateral security for the repayment of debit balances in the accounts.

Item 5. Interest in Securities of the Issuer.

Item 5(a) is hereby amended and restated to read as follows:

(a)           The aggregate percentage of Shares reported owned by each person named herein is based upon 120,473,465 Shares outstanding, which is the total number of Shares outstanding as of September 14, 2009 as reported in the Issuer’s definitive proxy statement on Schedule 14A filed with the Securities and Exchange Commission on October 7, 2009.

As of the close of business on October 23, 2009, Steel Partners II owned directly 15,396,138 Shares, constituting approximately 12.8% of the Shares outstanding.  By virtue of their relationships with Steel Partners II discussed in further detail in Item 2, each of Steel Holdings, Partners LLC, Steel Partners GP and Warren G. Lichtenstein may be deemed to beneficially own the Shares owned by Steel Partners II.

As of the close of business on October 23, 2009, Jack L. Howard beneficially owned 6,250 Shares underlying a Restricted Stock Award and beneficially owned an additional 12,500 Shares underlying Non-Qualified Stock Options that are exercisable within 60 days of the date hereof, constituting in the aggregate less than 1% of the Shares outstanding.  As of the close of business on October 23, 2009, John J. Quicke beneficially owned 6,250 Shares underlying a Restricted Stock Award and beneficially owned an additional 12,500 Shares underlying Non-Qualified Stock Options that are exercisable within 60 days of the date hereof, constituting in the aggregate less than 1% of the Shares outstanding.

Each Reporting Person, as a member of a “group” with the other Reporting Persons for purposes of Rule 13d-5(b)(1) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), may be deemed to beneficially own the Shares owned by the other Reporting Persons.

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CUSIP NO. 00651F108

Item 5(c) is hereby amended to add the following:

(c)           Schedule A annexed hereto lists all transactions in the Shares by the Reporting Persons since the filing of Amendment No. 14 to the Schedule 13D.  All of such transactions were effected in the open market pursuant to a 10b5-1 Purchase Trading Plan adopted by Steel Partners II.

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CUSIP NO. 00651F108

SIGNATURES

After reasonable inquiry and to the best of his knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated:  October 26, 2009	STEEL PARTNERS II, L.P.
	By:	Steel Partners II GP LLC General Partner
	By:	/s/ Sanford Antignas
		Sanford Antignas as Attorney-In-Fact for Warren G. Lichtenstein, Managing Member

STEEL PARTNERS HOLDINGS L.P.
By:	Steel Partners II GP LLC General Partner
By:	/s/ Sanford Antignas
	Sanford Antignas as Attorney-In-Fact for Warren G. Lichtenstein, Managing Member

STEEL PARTNERS LLC
By:	/s/ Sanford Antignas
	Sanford Antignas as Attorney-In-Fact for Warren G. Lichtenstein, Manager

STEEL PARTNERS II GP LLC
By:	/s/ Sanford Antignas
	Sanford Antignas as Attorney-In-Fact for Warren G. Lichtenstein, Managing Member

/s/ Sanford Antignas

Sanford Antignas

as Attorney-In-Fact for Warren G. Lichtenstein

Jack L. Howard

JACK L. HOWARD

John J. Quicke

JOHN J. QUICKE

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CUSIP NO. 00651F108

SCHEDULE A

Transactions in the Shares Since the Filing of Amendment No. 14 to the Schedule 13D

Class of Security Securities Purchased Price ($) Date of Purchase

STEEL PARTNERS II, L.P.

Common Stock	29,097	3.2483	10/12/09
Common Stock	37,700	3.2500	10/13/09
Common Stock	141,008	3.2500	10/16/09
Common Stock	195,422	3.2409	10/19/09
Common Stock	10,000	3.2500	10/20/09
Common Stock	241,651	3.2452	10/20/09
Common Stock	190,009	3.2490	10/21/09
Common Stock	991,034	3.2157	10/22/09
Common Stock	399,548	3.2486	10/23/09

STEEL PARTNERS HOLDINGS L.P.

None

STEEL PARTNERS LLC

None

STEEL PARTNERS II GP LLC

None

WARREN G. LICHTENSTEIN

None

JACK L. HOWARD

None

JOHN J. QUICKE

None

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