February 10, 2016
Sometimes the windows update DB can grow a lot !
In this case the SUSDB.mdf database is +8 GB ?
Use this tool WSUS_Cleanup_CL.exe to do the cleanup tasks
WSUS_Cleanup_CL.exe SERVERNAME f 80 ALL
For more WSUS command options and download see here
See also here for more cleanup options
November 23, 2015
Could not start Windows Update after a clean Windows 7 x64 Install ?
Go and look for C:\windows\WindowsUpdate.log to investigate the errors
Errors found in the log :
Agent * WU client version 7.3.7600.16385
Agent * Base directory: C:\Windows\SoftwareDistribution
DtaStor FATAL: Failed to initialize datastore, error = 0xC8000247
I found this extensive checklist : https://support.microsoft.com/en-us/kb/971058
This solved the problem at least on my side
More options can be found here : http://superuser.com/questions/951960/windows-7-sp1-windows-update-stuck-checking-for-updates