I have a few Windows 7 and Windows 2008/2008R2 VMs that occasionally take a while to do windows updates. If it does this then the first thing you should do is go to the Microsoft download site (www.microsoft.com/download) and search for KB947821. Download the correct version for your version of Windows Server and run it. This is non trivial in size (about 170M), and repairs issues it finds with the Windows update database.
This may or may not fix your windows update errors. The troubleshooter often doesn't work for me for fixing issues with Windows update but manually stopping and starting the services does fix Windows update for a time. I tried to follow the procedure in the link below but it fails to rename the software distribution folder. You can also delete the contents of the software distribution folder if it won't rename
However manually stopping and restarting the services does seem to fix windows update for a time. To do this follow the steps below.
Stop the BITS, Cryptographic, MSI Installer and the Windows Update Services. Type the following commands in the Command Prompt for this. Press the ENTER key after you type each command.
net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
Restart the BITS, Cryptographic, MSI Installer and the Windows Update Services. Type the following commands in the Command Prompt for this. Press the ENTER key after you type each command.
net start wuauserv
net start cryptSvc
net start bits
net start msiserver
After that windows update seems to come back for a while, I am actually using a scheduled task .vbs script found on the MSDN library and am looking into a way of doing it from the Hyper-V host to the clients. For right now I am doing windows updates via the vbs script and have it setup as a scheduled task. It works great; just make sure you have cscript setup before the file name to execute, otherwise it will fail.
ie. cscript windowsUpdate.vbs
