World of EUC

The agent should do this automatically at logon and logoff. Is that not happening?

Merge-Vhd <https://docs.microsoft.com/en-us/powershell/module/hyper-v/merge-vhd|https://docs.microsoft.com/en-us/powershell/module/hyper-v/merge-vhd>

According to my colleague, it is not happening automatically. It may have something to do with a file server crash, which have left some orphaned avhdx files on the file server

According to the documentation, FSLogix agent tries to merge RW files to base VHDX on Logon and logoff. Reason why they do this is to handle situations where, for example, a session was forcibly reset or machine powered off. Point is, it should be merged the next time the user logs on. A reason why the file is still there could be if the user is logged on to two sessions. In a "try RW, fallback to RO" setup, the RW file will be created when the first session launches. The second session will use RO file (in Windows temp). But the RW file will not be removed until the last session is closed, even if the last session is the RO one. This is because the RW file is still in use.