Job begins, but does not get past VSS, nor does it seem to fail.
(Job hangs with 0's across the board when viewing client > properties for the job and virtually no message logs available.)
Job fails due to network connectivity (reset by peer).
Disable VSS entirely to confirm whether or not this is a VSS issue. If the backup completes with VSS disabled, attempt to run a backup with VSS enabled but Include Writers disabled. This will determine whether it is all of VSS or just the Writers that is causing the issues. Also, try to run the following through the client diagnostics tab to view the writers. If it does not work (hangs up), have the customer attempt the same from the server itself.
VSSadmin list writers
If it works for the customer, have them send the output to us.
If running the above command hangs for the customer as well, have them try the following:
1) Try rebooting the machine and see if that fixes the "hang" problem
2) If not, let's make sure the service is NOT disabled
* Open Start Menu...right-click 'Computer' and select 'Manage'
* Go to the Services panel (Services and Applications - > Services)
* Find 'Volume Shadow Copy' in the list
* The 'Startup Type' value should NOT be 'Disabled'
* Change 'Startup Type' to 'Manual' if necessary
3) Try restarting the service from the 'Properties' dialog (see steps
* If service is running, click 'Stop' button to stop it
* Click the 'Start' button
* Check that the 'Service status' goes from 'Starting' to 'Started'
4) Try running 'VSSadmin list writers' again
In this example, the customer rebooted the server and the behavior did not reoccur.
Summary (as sent to the customer in the example):
From what we were able to speculate through troubleshooting, the reason the client started to hang up had to do with an issue with the VSS writers. (It is a common testing step to disable VSS on hung up or failed jobs to confirm or eliminate it as a factor in the issue.) Disabling VSS allowed the job to run successfully, with the side-effect that any open files were not backed up as is expected. From what they saw in the logs, our engineers suspected the VSS issue was linked to the VSS writers. This was confirmed when we could not bring up the writers using the CFA and you also could not bring up the writers from the server itself (using the command we sent you). This confirmed that there was not an issue on our side, rather the issue was on the server itself.
We have never encountered this behavior before, so our initial testing steps included either rebooting the server or stopping/starting the VSS services (if rebooting was not an option) to try to clear out whatever was hanging up the VSS writers. You had already done this, and the reboot appears to be what resolved the issue.
As far as root cause for the hang-up, unfortunately, that is beyond our area of expertise, especially considering the issue was with the VSS on the server and did not have anything to do with the CFA.