Hotfix KB938979 Windows Vista Performance Update intends to improve performance and reliability of Windows Vista system, however, some users reportedly that some problems have been caused by KB 938979 update. Other than failed uncertified driver signing issue, one of the reported issues is unable to rename or move folders after applying the patch.

The failure to rename or move files and folders issue seems to affect users installing official released KB938979 update from Microsoft (patch downloaded from Microsoft Download Centre) with vLite edited Windows Vista to remove some components or services. It also troubles those who applying unofficial or beta version of KB938979 Windows Vista Performance and Reliability Update Pack, including those who install the yet-to-be-confirmed and not even officially announced Service Pack 1 (SP1) all-on-one updates and hotfixes package for Windows Vista. It may also affects users who disable services or remove Windows Vista components manually, or install vLite integrated Windows Vista. Some reports that it randomly affects OEM version and non-vLite related of Windows Vista. But if you download your Windows Vista DVD ISO image from Internet from P2P network, there is high chance to catch this bug as the ISO may be modified.

To fix and solve the error in renaming or moving folders or files caused by KB938979, uninstalling the update itself won’t help. The problem is caused by some registry entries for Windows components listed below that must not be cleaned in the HKLM\Software\Microsoft\Windows\CurrentVersion\explorer\FolderDescriptions branch have been deleted:

Media Samples
Windows Search
Sync Center
Game Explorer
Printer Support

Thus the resolution to the failure to rename or move folders or files in Windows Vista is to add back the missing registry keys. Folks on forum (link dead) has exported a full clean export of all the related registry entries from a Windows Vista Ultimate system to a registry file to help those users affected by vLite. By merging the registry file to the affected Windows Vista’s registry, supposedly the missing registry keys will be restored, and it works for those using vLite, and should works to fix folders and files renaming and moving error caused by other reasons after installing KB938979.

The KB938979 bug fixes are now been put up on website. Download (no longer available) for x86 Vista and (no longer available) for x64 Vista. Unpack the archive, and double click the .reg file to merge the entries to registry. Ensure that you have KB938979 installed when you apply this registry fix.

For safety purpose, also backup the current registry key from HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\explorer\FolderDescriptions branch. Simply navigate to this branch in Registry Editor and export everything inside it.