That doesn't look good. Could you please reboot your computer and try again. If it fails again (which I assume but I kind of hope that the lock will be cleared after a reboot) please use the control panel immediately after that and create a mail support case through that.
I have this same issue. Not with a PST, but with an Exchange EDB file. It happens not only with backup explorer, but an access denied error as well from Windows Explorer when copying the file directly from the Veeam mounted directories.
Juts upgraded to latest version, 8.0.0.2021, did not resolve.
I have a very similar situation.
Get a message "Failed to transfer... Access to the path is denied."
I am trying to recover 3 GB SQL file. The rest - smaller files - are recovered without problems.
I also have Veeam Backup and Replication installed on the same machine, active support.
Tried to find out if I can use this more advanced tool to recover - their answer was to contact Endpoint team first.
I've also tried to upload the case via Endpoint itself, but it keeps telling me my email is not registered, although I've accepted online activation from email (tried even different emails to no avail.
Thanks, Dima, my email was finally registered, and I was able to submit the case.
Your colleague has contacted me, we are trying to troubleshoot with Veeam BR