Hi. Apologies for delay in responding.
Yes I did check for that and there was none. It occurred on at least 2 VMS I tried. In one case just shutting a VM down and trying to restart gave the missing vdi error. Everything I checked (with my limited knowledge of the CLI) looked fine. As soon as I rolled back to 7.4 on the master the VMS started without any issue.
Its as if the upgrade applied some schema changes to the vdi linking in some way perhaps?

I did try a second time just updating the master but with the same result - stopping and trying to restart a VM on any host (we have 4) gave the vdi missing error. Again rollling back fixed the problem but leaves me worried about upgrading.

Hi
Has there been any update on this please?

Just tried updating our pool and after updating the master had failed migration of VM (Ubuntu) and then was unable to get VM to start (Missing VDI error). Only solution was to roll master back to 7.4 and everything working again.

Thanks