UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A
(AMENDMENT NO. 1)

(Mark One)

x	ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended: December 31, 2006

¨	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For Transition period

Commission File Number of issuing entity: 333-130795-12

Washington Mutual Mortgage Pass-Through Certificates, WMALT Series 2006-4

Commission File Number of depositor: 333-130795

WAMU ASSET ACCEPTANCE CORP.

(Exact name of depositor as specified in its charter)

WASHINGTON MUTUAL MORTGAGE SECURITIES CORP.

(Exact name of sponsor as specified in its charter)


	Delaware
	(State or other jurisdiction of Incorporation or organization of the issuing entity)

	1301 Second Avenue, WMC 3501A Seattle, Washington 98101
	(Address of principal executive offices of issuing entity)

	(206) 500-4418
	(Telephone number, including area code)

	54-2195748
	(I.R.S. Employer Identification No.)

	N/A
	(Former name, former address, if changed since last report)

Securities registered pursuant to Section 12(b) of the Act: None

Securities Registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ¨ No x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ¨ No x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 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. x Yes ¨ No

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part II of the Form 10-K or any amendment to this form 10-K. ¨ [Item 405 of Regulation S-K is not applicable.]

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer. See definition of “accelerated filer and large accelerated filer” in Rule 12b-2 of the Exchange Act. (Check one):

Large accelerated filer ¨ Accelerated filer ¨ Non-accelerated filer x

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ¨ No x

Registrant has no voting or non-voting common equity outstanding held by non-affiliates.

PART III

The Item labeled "Item 1122 of Regulation AB: Compliance with Applicable Servicing Criteria." is hereby amended by replacing the last sentence thereof with the following:

None of the Servicing Reports or Attestation Reports has identified any material instance of noncompliance with the servicing criteria as applicable to the respective Servicing Party, except that, with respect to:

1. WMMSC and its compliance with Item 1122 (d)(2)(vii)(B), two of twelve bank statement reconciliations examined were not prepared within 30 calendar days after the bank statement cutoff date, but were prepared within 30 calendar days after month end, which was 32 calendar days after the bank statement cutoff date.

2. American Security Insurance Company and Standard Guaranty Insurance Company (together, "Assurant") and their compliance with Item 1122(d)(4)(xii), during the reporting period covered by this 10-K Annual Report, Assurant did not have sufficient policies and procedures in place to capture the information necessary to determine its compliance with Item 1122(d)(4)(xii). As stated in a letter dated January 30, 2008 and attached hereto as an exhibit to this 10-K/A, Assurant has implemented policies and procedures to capture the information required to comply with this provision.

PART IV

Item 15. Exhibits, Financial Statement Schedules.

(a)(1)

Not Applicable.

(a)(2)

Not Applicable.

(a)(3)

Not Applicable.

(b)

Exhibits

Exhibit No.		Exhibit Description

4.1*		Pooling and Servicing Agreement (incorporated herein by reference from Exhibit 4.1 to the Form 8-K filed by the issuing entity on May 12, 2006).
4.2*		Mortgage Loan Purchase Agreement (incorporated herein by reference from Exhibit 4.7 to the Form S-3 filed by WaMu Asset Acceptance Corp. on December 12, 2005 with respect to Registration Statement No. 333-130795).
4.3*		Amended and Restated Administrative Agent Agreement (incorporated herein by reference from Exhibit 4.9 to the Form 8-K filed by WaMu Asset Acceptance Corp. on March 6, 2006 with respect to Registration Statement No. 333-130795).
31*		Certification of Thomas G. Lehmann pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31.2**		Restated Certification of Thomas G. Lehmann pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
33.1*		Report on Assessment of Compliance with Servicing Criteria for WaMu Asset Acceptance Corp.
33.2*		Report on Assessment of Compliance with Servicing Criteria for Washington Mutual Bank.
33.3*		Report on Assessment of Compliance with Servicing Criteria by Washington Mutual Mortgage Securities Corp.
33.4*		Report on Assessment of Compliance with Servicing Criteria for Washington Mutual Bank fsb.
33.5*		Report on Assessment of Compliance with Servicing Criteria for American Security Insurance Company and Standard Guaranty Insurance Company.
33.6*		Report on Assessment of Compliance with Servicing Criteria for LaSalle Bank National Association.
33.7***	Restated Report on Assessment of Compliance with Servicing Criteria for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure Insurance Agency, Inc.
33.8***	Letter dated January 30, 2008 regarding Restated Assessment for the Reporting Period of January 1, 2006 through December 31, 2006 for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure Insurance Agency, Inc.
34.1*	Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria for WaMu Asset Acceptance Corp.
34.2*	Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria by Washington Mutual Bank.
34.3*	Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria by Washington Mutual Mortgage Securities Corp.
34.4*	Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria by Washington Mutual Bank fsb.
34.5*	Attestation Report of PriceWaterhouseCoopers on Assessment of Compliance with Servicing Criteria for American Security Insurance Company and Standard Guaranty Insurance Company.
34.6*	Attestation Report of Ernst & Young LLP on Assessment of Compliance with Servicing Criteria for LaSalle Bank National Association.
34.7****		Restated Attestation Report of PriceWaterhouseCoopers on Assessment of Compliance with Servicing Criteria for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure Insurance Agency, Inc.
35.1*		Servicer Compliance Statement of Washington Mutual Bank.
35.2*		Servicer Compliance Statement of Washington Mutual Mortgage Securities Corp.
99.1*		Excerpt from Section 2 of the Term Sheet (incorporated herein by reference from Exhibit 99.1 to the Form 8-K filed by the issuing entity on May 12, 2006).

_________________________________

*		Previously Filed
**		Exhibit 31.2 replaces previously filed Exhibit No. 31
***		Exhibits 33.7 and 33.8 replace previously filed Exhibit No. 33.5
****		Exhibit 34.7 replaces previously filed Exhibit 34.5

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: May 9, 2008

	WAMU ASSET ACCEPTANCE CORP.


		By: /s/ David Beck
		Name: David Beck
		Title: President and Senior Officer in Charge of Securitization of the Depositor

EXHIBIT INDEX

Exhibit No.		Exhibit Description

4.1*		Pooling and Servicing Agreement (incorporated herein by reference from Exhibit 4.1 to the Form 8-K filed by the issuing entity on May 12, 2006).
4.2*		Mortgage Loan Purchase Agreement (incorporated herein by reference from Exhibit 4.7 to the Form S-3 filed by WaMu Asset Acceptance Corp. on December 12, 2005 with respect to Registration Statement No. 333-130795).
4.3*		Amended and Restated Administrative Agent Agreement (incorporated herein by reference from Exhibit 4.9 to the Form 8-K filed by WaMu Asset Acceptance Corp. on March 6, 2006 with respect to Registration Statement No. 333-130795).
31*		Certification of Thomas G. Lehmann pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31.2**		Restated Certification of Thomas G. Lehmann pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
33.1*		Report on Assessment of Compliance with Servicing Criteria for WaMu Asset Acceptance Corp.
33.2*		Report on Assessment of Compliance with Servicing Criteria for Washington Mutual Bank.
33.3*		Report on Assessment of Compliance with Servicing Criteria by Washington Mutual Mortgage Securities Corp.
33.4*		Report on Assessment of Compliance with Servicing Criteria for Washington Mutual Bank fsb.
33.5*		Report on Assessment of Compliance with Servicing Criteria for American Security Insurance Company and Standard Guaranty Insurance Company.
33.6*		Report on Assessment of Compliance with Servicing Criteria for LaSalle Bank National Association.
33.7***	Restated Report on Assessment of Compliance with Servicing Criteria for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure Insurance Agency, Inc.
33.8***	Letter dated January 30, 2008 regarding Restated Assessment for the Reporting Period of January 1, 2006 through December 31, 2006 for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure Insurance Agency, Inc.
34.1*	Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria for WaMu Asset Acceptance Corp.
34.2*	Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria by Washington Mutual Bank.
34.3*	Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria by Washington Mutual Mortgage Securities Corp.
34.4*	Attestation Report of Deloitte & Touche LLP on Assessment of Compliance with Servicing Criteria by Washington Mutual Bank fsb.
34.5*	Attestation Report of PriceWaterhouseCoopers on Assessment of Compliance with Servicing Criteria for American Security Insurance Company and Standard Guaranty Insurance Company.
34.6*	Attestation Report of Ernst & Young LLP on Assessment of Compliance with Servicing Criteria for LaSalle Bank National Association.
34.7****		Restated Attestation Report of PriceWaterhouseCoopers on Assessment of Compliance with Servicing Criteria for American Security Insurance Company, Standard Guaranty Insurance Company and TrackSure Insurance Agency, Inc.
35.1*		Servicer Compliance Statement of Washington Mutual Bank.
35.2*		Servicer Compliance Statement of Washington Mutual Mortgage Securities Corp.
99.1*		Excerpt from Section 2 of the Term Sheet (incorporated herein by reference from Exhibit 99.1 to the Form 8-K filed by the issuing entity on May 12, 2006).

_________________________________

*		Previously Filed
**		Exhibit 31.2 replaces previously filed Exhibit No. 31
***		Exhibits 33.7 and 33.8 replace previously filed Exhibit No. 33.5
****		Exhibit 34.7 replaces previously filed Exhibit 34.5

Washington Mutual Mortgage Pass-Through Certificates, WMALT Series 2006-4 10-K/A