daviid Mar 25 11:12AM 2018 GUI
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.
gchen Mar 25 8:40PM 2018
The 80042316 error means another VSS operation was underway at that time. You can find more details in the Window Event Viewer.
daviid Mar 26 8:51PM 2018
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}
saspus Apr 2 12:46AM 2018
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.