Error: Volume Shadow Copy Error 0x800423f2 - writer error: timeout (4037547)

You may notice that backups are failing for an Agent with error:

Volume Shadow Copy Error 0x800423f2 - writer error: timeout 

Windows Registry Disclaimer:

Quest does not provide support for problems that arise from improper modification of the registry. The Windows registry contains information critical to your computer and applications. Make sure you back up the registry before modifying it. For more information on the Windows Registry Editor and how to back up and restore it, refer to Microsoft Article ID 256986 “Description of the Microsoft Windows registry” at Microsoft Support.

1. Manually extend the VSS timeout by editing the following registry key: "HKLM\Software\Microsoft\Windows NT\CurrentVersion\SPP\CreateTimeout".
2. Change value to 12000000 (2*10*60*1000 = 20 mins).
3. The default for the timeout period is 10 mins so hopefully doubling this will give enough time to complete the snapshot.
4. If this isn't present, you'll need to manually enter the registry key. It's a DWORD 32-bit key.
5. Note: Always backup the Registry before making any changes.