Welcome to the Community,
I don't see a reason why the VM shouldn't work. Please provide more information about the issue, i.e. error messages, log files, ... to find out what's causing the issue.
One reason I can think of is that the VM may have been suspended with the old version. In this case you'd see a .vmss, file in the VMs folder. Deleting this file may already solve the issue.
Please note that deleting the file will cause a hard reset, comparable to pulling the power plug on a physical system, so ensure that you have a backup of the VM's files, so that you can restore the current state.
André
