How to Fix Error Code:(0×80073712) Installing Vista Service Pack 1

When you try to install Vista SP1 from windows update you may receive the error code 0×80073712

Background

The issue is that the WUA 3.0 upgrade is corrupted ,essentially the system reports the WUA to be version 3.0 but the files are old version (such as wups.dll, wuaueng.dll etc in “windows\system32″). Also you cannot reinstall WUA manually

Solution

Delete the file:

C:\windows\winsxs\pending.xml

Try Installing Updates again
If you and access denied error message follow the next instructions

Access Denied Error

Make a note of the file that has the access denied error
Login as an account with adminstrators access
Right-click the file that you want to take ownership of, and then click Properties.

Click the Security tab, and then click OK on the Security message (if one appears).
Click Advanced, and then click the Owner tab.

In the Name list, click Administrator, or click the Administrators group, and then click OK.
The administrator or the Administrators group now owns the file.
Click Add to add a new user

In the Enter the object names to select (examples) list, type the user or group account that you want to give access to the file. For example, type Everyone.
Click OK.
In the Group or user names list, click the account that you want, and then select the check boxes of the permissions that you want to assign that user. Click full control in this case.