The error may be reported as VSS backups are failing randomly after backing up 30 or 50 machines:

Volume Shadow Copy Error 0x800423f2 - writer error: timeout

Manual backups are always successful.

Others errors:

"VSS: Bad state.(C:\)(\\?\Volume{aaf24c44-54b3-11e0-bd6f-806e6f6e6963}\)"

"Failed to perform a shadow copy for \\DSP-A-FP02\C$\"

"The process cannot access the file because it is being used by another process. "

"Volume Shadow Copy Error 0x800423f2 - writer error: timeout"



VSS time out during backup.

Windows disk I/O process taking long time to complete and causing the VSS failure.

Windows has VSS time out value hard coded in the registry and its set to 1200000 which is 20 minutes.

In DS-Client setup>Conguration>Advanced>Communication>Parameter>VSSKeepAliveTimeout

Default value is 300 which is 5 minutes


If vssadmin delete shadows /all did not help, then try the below workaround:

1. Change the VSS time out value in DS-Client:

DS-Client setup>Conguration>Advanced>Communication>Parameter>VSSKeepAliveTimeout

Default value is 300 which is 5 minutes.

We can change the value up to 20 minutes but if more time is required then make a change in the registry, but most of the time extending the value from 5 minutes to 10 minutes resolve the issue.

2. If 1 did not help, then make changes in the Windows registry:

Depending upon windows version:

Windows 2008/R2:

Using the registry editor, "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\SPP"

- If need be, create a new registry value of type DWORD with name "CreateTimeout"

- Change value to 12000000(2*10*60*1000 = 20 mins) in decimal


Windows 2012/R2

You can increase the VSS timeout period by adjusting the registry keys for VSS on that particular machine:


Under this directory, you can create a value labeled IdleTimeout and set type to DWORD, then input the timeout period between 1 and FFFFFFFF.

The "CreateTimeout" key should be added as a DWORD 32-bit, and it's value is in milliseconds. The default value for older Windows editions was 10 minutes, but I think it has been reduced significantly with 2008R2, to something like 1 minute. You might try increasing this value if you are using VSS on a system that is consistently busy. Many users and KB articles for backup products suggest using 1200000 which is 20 minutes.

If backing up virtual machines, check inside the VMs in the Event Viewer for more detail errors, use low level debug tools like vsstrace ( to determine the cause.

Please increase RAM and free disk space and test the backup again.

Please also check different types of applications which make VSS timeout errors more likely: Some antivirus software may create an incompatibility. Try uninstalling it (not just switching off real-time scanning). In addition, make sure no defragmentation, antivirus scans, or any other heavy hard drive activity is taking place when initiating the backup, we find the that running manual backup is always successful.

Also check Microsft Article: VSS time outs during backups:

If issues is experience during Exchange backup check Microsoft Article: