Visual Studio 2005 SP1: didn’t pass the digital signature policy error

To solve this follow the work around:

Work Arround 1:

1. Start Menu, click Run, type > control admintools and then click OK.
2. Double-click Local Security Policy.
3. Click Software Restriction Policies.
   Note: If no software restrictions are listed, right-click Software Restriction Policies, and then click Create New Policy.
4. Under Object Type, double-click Enforcement.
5. Click All users except Local Administrators, and then click OK.
6. Restart the computer.

Install SP1 with no errors.

Work Arround 2:

There is a fix from Microsoft to resolve the issue. Please visit the following knowledge base article:

http://support.microsoft.com/kb/925336 or Download the Update for Windows Server 2003 (KB925336).

Note: Revert the settings after the installation is over.