Using GUI 2.10 (Win10), I get the error “Shadow copy creation failed: StartSnapshotSet returned 80042316”.
This is after Duplicacy loads the latest snapshot from the cache, fetches chunks, regards the most recent revision, and then attempts to create a shadow copy for the repository. In this case the source is OS drive and I am backing up to Google Drive, and the VSS option is enabled.
The 80042316 error means another VSS operation was underway at that time. You can find more details in the Window Event Viewer.
This is the error:
Volume Shadow Copy Service error: Unexpected error querying for the IVssWriterCallback interface. hr = 0x80070005, Access is denied.
. This is often caused by incorrect security settings in either the writer or requestor process.
Operation:
Gathering Writer Data
Context:
Writer Class Id: {e8132975-6f93-4464-a53e-1050253ae220}
Writer Name: System Writer
Writer Instance ID: {5a7816b3-498b-4c33-a0b2-ec0e36d89518}
Occasionally sublte filesystem corruption causes weird issues with VSS on Windows.
In elevated command prompt run chkdsk c: /f, say Y to check on the next reboot, and reboot.
Windows should check the filesystem upon the subsequent boot. If it finds issues - it will fix them and reboot.
If it continues booting - then it did not find any issues.
See if after that your VSS issue “magically” dissapears.
Note, if it does not check disk during next boot – and I have seen that happen – it is most likely the file “autochk.exe” got corrupted. I don’t know why and how it gets corrupted but I have witness that way too many times for it to be a coincidence. Copy it from another windows machine and retry the check disk.