SymptomsThe error is reported when running a backup session for a file system backup set configured with VSS option or for VSS-Aware backup sets .
The error may be also reported for file system backup sets without the VSS option enabled if the System State is included in the backup selection and the operating system on the backup source computer is Windows OS 2012R2 and up.
Cause(s)1) The Remote Registry service is not started or is disabled on the backup source computer.
2) The Volume Shadow Copy service is disabled on the backup source computer.
3) The VSS System Writer is missing or inactive on the backup source computer running Windows 2008R2 and up.
4) The file "vss_ps.dll" may be un-registered, and needs to be registered again.
Workaround(s)1) Set to 'Automatic' and start the Remote Registry service on the backup source computer if the backup source computer runs Windows 2008 R2 or older. If the backup source computer runs Windows 2012 and newer the Remote Registry service is stopped and has the start up type set to 'Automatic (Trigger Start)', in such scenario no action is needed as the DS-Client application will send first a start command to the Remote Registry service, then proceed with the additional tasks to create a volume shadow copy and dump the system state.
2) Enable the Volume Shadow Copy service on the backup source computer and set it to 'manual', no need to start it as the DS-Client application will send first a start command to this service and then proceed with the volume shadow copy creation,
3) Check if the entry 'System Writer' is displayed when running the following command in a command line window: vssadmin list writers. If it is not displayed, please follow the steps described here: http:social.technet.microsoft.com/Forums/en/winserverfiles/thread/1d251271-d332-40b4-9a98-d03653553504 the last step from the link mentioned above is described below and very likely applying only this step will fix the problem ( if not then perform all steps ): CD c:\windows\system32 Takeown /f %windir%\winsxs\filemaps\* /a icacls %windir%\winsxs\filemaps\*.* /grant "NT AUTHORITY\SYSTEM:(RX)" icacls %windir%\winsxs\filemaps\*.* /grant "NT Service\trustedinstaller:(F)" icacls %windir%\winsxs\filemaps\*.* /grant "BUILTIN\Users:(RX)" After that, run again the command "vssadmin list writers" and check that the 'System Writer' entry appears in the list, then run a test backup to verify that error is not reported anymore.
4) The solution is to re-register the file "vss_ps.dll" by running the command in a command line window: