If Windows Server backup occassionally gives you a timeout, and you get the following error:

Error
The shared protection point operation failed with error 0x81000101.

This error is caused when the volume shadow copy is taking more than 10 minutes and is timing out. You can try to increase the timeout value to fix this issue. This is done by adding a registry key:

Fire up regedit.

Navigate to key HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\SPP.

Create a new DWORD value with name CreateTimeout, set its value to the number of millis.
For 20 minutes this would be decimal 12000000 (20·60·1000).

Try re-running the backup. The timeout should no longer occur.   ...