If you have problems with the resolution in this article, no-charge support is available by calling 1-866-PCSAFETY in the United States and Canada or by contacting your local Microsoft subsidiary. For more information about how to contact your local Microsoft subidiary for security update support issues, visit the International Support Web site: Enterprise customers can obtain support for security updates through their usual support contacts.

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When you try to install an update for the Microsoft .NET Framework 1.0, for the Microsoft .NET Framework 1.1, the Microsoft .NET Framework 2.0, the Microsoft .NET Framework 3.0, or for the Microsoft .NET Framework 3.5, you may receive the following Microsoft Windows Update error code: Or, you may receive the following Microsoft Windows Installer error code: This problem may occur when you use certain system configurations.

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Windows Update error code "0x643" and Windows Installer error code "1603" are generic error codes. Typically, these error codes mean that the update was not installed. These errors codes are usually caused by a corruption in the .NET Framework installation or by an inconsistency on the MSI database state.

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To successfully install the update, uninstall all the versions of the .NET Framework on the computer, and then reinstall all the versions of the .NET Framework on the computer. You may have to work through more than one of the following methods.

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Method 1: Manually remove and reinstall .NET Framework

To manually remove and reinstall the .NET Framework, follow these steps:

1.	Remove the .NET Framework. a. Click Start, and then click Control Panel. b. Double-click Add or Remove Programs. c. Note each version of the .NET Framework that is already installed on the computer. Then, uninstall all the versions of the .NET Framework. d. When you are prompted, restart the computer.
2.	Use the Windows Installer CleanUp Utility to clean up the MSI database state for all the versions of the .NET Framework. a. Download the Windows Installer CleanUp Utility. The following file is available for download from the Microsoft Download Center: Download the Windows Installer CleanUp Utility package now. (http://download.microsoft.com/download/e/9/d/e9d80355-7ab4-45b8-80e8-983a48d5e1bd/msicuu2.exe) For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base: 119591 (http://support.microsoft.com/kb/119591/) How to obtain Microsoft support files from online services Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file. b. Install the Windows Installer CleanUp Utility as an administrator or as a user account that is a member of the local Administrators group. c. Click Start, point to All Programs, and then click Windows Install Cleanup. d. In the Windows Installer CleanUp Utility, remove all Windows Installer applications for the .NET Framework.
3.	Restart the computer.
4.	Download and then reinstall all the versions of the .NET Framework that were previously installed on the computer. To download the .NET Framework 1.0, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?FamilyID=d7158dee-a83f-4e21-b05a-009d06457787&DisplayLang=en (http://www.microsoft.com/downloads/details.aspx?FamilyID=d7158dee-a83f-4e21-b05a-009d06457787&DisplayLang=en) To download the .NET Framework 1.0 Service Pack 3, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?familyid=6978D761-4A92-4106-A9BC-83E78D4ABC5B&displaylang=en (http://www.microsoft.com/downloads/details.aspx?familyid=6978D761-4A92-4106-A9BC-83E78D4ABC5B&displaylang=en) To download the .NET Framework 1.1, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?familyid=262D25E3-F589-4842-8157-034D1E7CF3A3&displaylang=en (http://www.microsoft.com/downloads/details.aspx?familyid=262D25E3-F589-4842-8157-034D1E7CF3A3&displaylang=en) To download the .NET Framework 1.1 Service Pack 1, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?familyid=A8F5654F-088E-40B2-BBDB-A83353618B38&displaylang=en (http://www.microsoft.com/downloads/details.aspx?familyid=A8F5654F-088E-40B2-BBDB-A83353618B38&displaylang=en) To download the .NET Framework 2.0, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?FamilyID=0856eacb-4362-4b0d-8edd-aab15c5e04f5&DisplayLang=en (http://www.microsoft.com/downloads/details.aspx?FamilyID=0856eacb-4362-4b0d-8edd-aab15c5e04f5&DisplayLang=en) To download the .NET Framework 2.0 Service Pack 1, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?familyid=79BC3B77-E02C-4AD3-AACF-A7633F706BA5&displaylang=en (http://www.microsoft.com/downloads/details.aspx?familyid=79BC3B77-E02C-4AD3-AACF-A7633F706BA5&displaylang=en) To download the .NET Framework 3.0, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?familyid=10CC340B-F857-4A14-83F5-25634C3BF043&displaylang=en (http://www.microsoft.com/downloads/details.aspx?familyid=10CC340B-F857-4A14-83F5-25634C3BF043&displaylang=en) To download the .NET Framework 3.0 Service Pack 1, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?familyid=EC2CA85D-B255-4425-9E65-1E88A0BDB72A&displaylang=en (http://www.microsoft.com/downloads/details.aspx?familyid=EC2CA85D-B255-4425-9E65-1E88A0BDB72A&displaylang=en) To download the .NET Framework 3.5, visit the following Microsoft Web site: http://www.microsoft.com/downloads/details.aspx?familyid=333325FD-AE52-4E35-B531-508D977D32A6&displaylang=en (http://www.microsoft.com/downloads/details.aspx?familyid=333325FD-AE52-4E35-B531-508D977D32A6&displaylang=en)
5.	When you are prompted, restart the computer.

Note When you have reinstalled all the versions of the .NET Framework, you can use Windows Update to check for updates to the .NET Framework.

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Method 2: Use the .NET Framework automatic cleanup tool

This tool is not intended as a substitute for the standard uninstall procedure. You should try to perform an uninstall by using the steps in Method 1, earlier in this article, before you use this cleanup tool.

The .NET Framework cleanup tool removes the .NET Framework for you. For information about how to obtain and use this tool, visit the following MSDN Web site: Note This cleanup tool deletes shared files and registry keys that are used by multiple versions of the .NET Framework. To guarantee that all versions of the .NET Framework work correctly, if you run the cleanup tool to remove the .NET Framework, you must first remove all installed versions of the .NET Framework by using this cleanup tool. Then, you must reinstall all the previously installed versions starting with the lowest version number.

Suppose that you have the .NET Framework 1.1 and the .NET Framework 2.0 installed on your computer, and you plan to use this cleanup tool. In this scenario, you should use the cleanup tool to first remove the .NET Framework 1.1, and then use the cleanup tool to remove the .NET Framework 2.0. After you have removed both versions, you would then reinstall .NET Framework 1.1, and then install the .NET Framework 2.0, in that sequence.

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

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You may experience this problem when you use any of the following configurations:

•	Microsoft .NET Framework 1.0 Service Pack 3 when you use it with any of the following operating systems: • Microsoft Windows 2000 Advanced Server Service Pack 4 (SP4) • Microsoft Windows 2000 Datacenter Server SP4 • Microsoft Windows 2000 Professional SP4 • Microsoft Windows 2000 Server SP4 • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP1 • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP2 • Windows Server 2003, Datacenter Edition SP1 • Windows Server 2003, Datacenter Edition SP2 • Windows Server 2003, Datacenter x64 Edition SP2 • Windows Server 2003, Datacenter x64 Edition • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP1 • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP2 • Windows Server 2003, Enterprise Edition SP1 • Windows Server 2003, Enterprise Edition SP2 • Windows Server 2003, Enterprise x64 Edition SP2 • Windows Server 2003, Enterprise x64 Edition • Windows Server 2003, Standard Edition 32-bit x86 SP1 • Windows Server 2003, Standard Edition 32-bit x86 SP2 • Windows Server 2003, Standard x64 Edition SP2 • Windows Server 2003, Standard x64 Edition • Windows Server 2003, Web Edition SP1 • Windows Server 2003, Web Edition SP2 • Windows Vista Business • Windows Vista Enterprise • Windows Vista Home Basic • Windows Vista Home Premium • Windows Vista Ultimate • Windows XP Home Edition SP2 • Windows XP Media Center Edition 2005 • Windows XP Professional SP2 • Windows XP Professional x64 Edition • Windows XP Professional x64 Edition SP2 • Windows XP Tablet PC Edition SP2
•	Microsoft .NET Framework 1.1 Service Pack 1 when you use it with any of the following operating systems: • Windows 2000 Advanced Server SP4 • Windows 2000 Datacenter Server SP4 • Windows 2000 Professional SP4 • Windows 2000 Server SP4 • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP1 • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP2 • Windows Server 2003, Datacenter Edition SP2 • Windows Server 2003, Datacenter x64 Edition SP2 • Windows Server 2003, Datacenter x64 Edition • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP1 • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP2 • Windows Server 2003, Enterprise Edition SP2 • Windows Server 2003, Enterprise x64 Edition SP2 • Windows Server 2003, Enterprise x64 Edition • Windows Server 2003, Standard Edition 32-bit x86 SP2 • Windows Server 2003, Standard x64 Edition SP2 • Windows Server 2003, Standard x64 Edition • Windows Server 2003, Web Edition SP2 • Windows Vista Business • Windows Vista Enterprise • Windows Vista Home Basic • Windows Vista Home Premium • Windows Vista Ultimate • Windows XP Home Edition SP2 • Windows XP Media Center Edition 2005 • Windows XP Professional SP2 • Windows XP Professional x64 Edition • Windows XP Professional x64 Edition SP2
•	Microsoft .NET Framework 2 or Microsoft .NET Framework 2 SP1 when you use it with any of the following operating systems: • Windows 2000 Advanced Server SP4 • Windows 2000 Datacenter Server SP4 • Windows 2000 Professional SP4 • Windows 2000 Server SP4 • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP1 • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP2 • Windows Server 2003, Datacenter Edition SP1 • Windows Server 2003, Datacenter Edition SP2 • Windows Server 2003, Datacenter x64 Edition • Windows Server 2003, Datacenter x64 Edition SP2 • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP1 • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP2 • Windows Server 2003, Enterprise Edition SP1 • Windows Server 2003, Enterprise Edition SP2 • Windows Server 2003, Enterprise x64 Edition • Windows Server 2003, Enterprise x64 Edition SP2 • Windows Server 2003, Standard Edition 32-bit x86 SP1 • Windows Server 2003, Standard Edition 32-bit x86 SP2 • Windows Server 2003, Standard x64 Edition • Windows Server 2003, Standard x64 Edition SP2 • Windows Server 2003, Web Edition SP1 • Windows Server 2003, Web Edition SP2 • Windows XP Home Edition SP2 • Windows XP Media Center Edition 2005 • Windows XP Professional SP2 • Windows XP Professional x64 Edition • Windows XP Professional x64 Edition SP2 • Windows XP Tablet PC Edition SP2
•	Microsoft .NET Framework 3.0 or Microsoft .NET Framework 3.0 SP1 when you use it with any of the following operating systems: • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP1 • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP2 • Windows Server 2003, Datacenter Edition SP1 • Windows Server 2003, Datacenter Edition SP2 • Windows Server 2003, Datacenter x64 Edition • Windows Server 2003, Datacenter x64 Edition SP2 • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP1 • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP2 • Windows Server 2003, Enterprise Edition SP1 • Windows Server 2003, Enterprise Edition SP2 • Windows Server 2003, Enterprise x64 Edition • Windows Server 2003, Enterprise x64 Edition SP2 • Windows Server 2003, Standard Edition 32-bit x86 SP1 • Windows Server 2003, Standard Edition 32-bit x86 SP2 • Windows Server 2003, Standard x64 Edition • Windows Server 2003, Standard x64 Edition SP2 • Windows Server 2003, Web Edition SP1 • Windows Server 2003, Web Edition SP2 • Windows XP Home Edition SP2 • Windows XP Media Center Edition 2005 • Windows XP Professional SP2 • Windows XP Professional x64 Edition • Windows XP Professional x64 Edition SP2 • Windows XP Tablet PC Edition SP2
•	Microsoft .NET Framework 3.5 when you use it with any of the following operating systems: • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP1 • Windows Server 2003, Datacenter Edition for Itanium-based Systems SP2 • Windows Server 2003, Datacenter Edition SP1 • Windows Server 2003, Datacenter Edition SP2 • Windows Server 2003, Datacenter x64 Edition • Windows Server 2003, Datacenter x64 Edition SP2 • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP1 • Windows Server 2003, Enterprise Edition for Itanium-based Systems SP2 • Windows Server 2003, Enterprise Edition SP1 • Windows Server 2003, Enterprise Edition SP2 • Windows Server 2003, Enterprise x64 Edition • Windows Server 2003, Enterprise x64 Edition SP2 • Windows Server 2003, Standard Edition 32-bit x86 SP1 • Windows Server 2003, Standard Edition 32-bit x86 SP2 • Windows Server 2003, Standard x64 Edition • Windows Server 2003, Standard x64 Edition SP2 • Windows Server 2003, Web Edition SP1 • Windows Server 2003, Web Edition SP2 • Windows Vista Business • Windows Vista Enterprise • Windows Vista Home Basic • Windows Vista Home Premium • Windows Vista Ultimate • Windows XP Home Edition SP2 • Windows XP Media Center Edition 2005 • Windows XP Professional SP2 • Windows XP Professional x64 Edition • Windows XP Professional x64 Edition SP2 • Windows XP Tablet PC Edition SP2

For more information about another error message that you may receive when you try to install this update, click the following article number to view the article in the Microsoft Knowledge Base:

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