I suspended the VM last night, and later attempted to revive it. Could not activate the password box - mouse pointer was missing. Clicked on Shut Down, but after warning message appeared I did not click the second time. Closed Parallels, re-opened, and now all items on the Virtual Macine menu are greyed except for Suspend. The VM window is working (resize, show/hide menu button,...) but the menu items Start etc are inactive. At least files are accessible via Parallels Explorer. It may be tied to the latest update. When I reopened parallels, I got a window congratulating me on the update. I'm getting alarmed about this.
I rebooted OSX. That solved the stuckness problem. On starting the VM again, Parallels gave the message "The virtual machine XYZ cannot be resumed. It is impossible to restore the virtual machine state because the file containing this state has a wrong checksum. The virtual machine will be restarted." The VM is now running normally.
