Unable to update the Service pack / Windows Update is not working / Update files are not installing

Issue : Unable to update the Service pack / Windows Update is not working / Update files are not installing, And you will be getting below error messages while updating Windows / installing updates.

Serive pack Install error

Unable to install SP2

Windows Update error

General Troubleshooting :

Run below command in elevated command prompt (Run As Administrator)

sfc /scannow

Refer the sfc /scannow log files in %windir%/Logs/CBS/CBS.log

If you found any corrupted files, Replace those files from workig system.

Refer :  MS KB: http://support.microsoft.com/kb/929833

Also download and run System Update Readiness Tool and check that fixes the problem (http://support.microsoft.com/kb/947821).

After installing SURTool run below command in elevated command prompt.

DISM.exe /Online /Cleanup-image /Scanhealth
DISM.exe /Online /Cleanup-image /Restorehealth

Refer below links to Analyze Checksur.log / CBS.log files.

http://www.thewindowsclub.com/checksur-system-update-readiness-tool
http://www.sevenforums.com/tutorials/108805-system-update-readiness-tool-checksur-log-file-analyzis.html

If above steps didn’t work, Try repairing the OS / try in-place upgrade for the OS.

Refer : http://support.microsoft.com/kb/2255099