It is obviously preferable, and conducive to more reliable restores, for all applications to be closed at the backup time, but there are many cases where this is not possible, thus Microsoft has created the Volume Shadow Copy Service (VSS) to back up open files on the local machine in a crash-resistant state, i.e. files that are open and in use by applications at the backup time. So, our software utilizes VSS by default, though it can be turned off in GUI or via the INI file using the vss option as described below.
On some machines, you will encounter VSS errors or warnings during backup such as “Warning, VSS [StartSnapshotSet returned VSS_E_BAD_STATE].” These VSS problems sometimes result from (a) multiple different backup solutions, (b) something wrong with the configuration of VSS on the local computer, and (c) other reasons.
If you see an error message similar to: "Please check the Event Viewer in Microsoft Windows Administrative Tools for more information on why Microsoft Volume Shadow Services failed to start."
You can run this command in a terminal to see which writer is the issue.
vssadmin list writers
e.g. result:
Writer name: 'Shadow Copy Optimization Writer'
Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
Writer Instance Id: {4501652f-d6b3-4765-8f5a-ce23d34929e5}
State: [1] Stable <------ STABLE - we want to see this!
Last error: No error <------ NO ERROR - we want to see this!
Generally, when we see these VSS errors the fastest way to get them back into a good state is by rebooting the machine.
If the issue persists after the reboot then you may need to follow Microsoft Guidelines for addressing troublesome vss writers.
If you do not need to backup open files then you can turn off our software’s usage of VSS by setting vss to zero in the INI file or by launching the GUI in expert mode and choosing the following on the Expert Settings tab:
