I attempted to open an app I use every day in Win10 but the app never appeared and Win10 hung trying to open it. I then tried to close down the VM completely but Win10 hung on the shutdown. I was unable to send a Ctrl-Alt-Del to get to the task window of Win10 which was waiting to end the app load. I then had to force quit Parallels. On reloading Parallels, the control window showed Win10 continuing to hang in "Stopping" mode. How do I get out of this situation? Thanks.
Update to my problem: It appears to be a macOS issue. I'm on Mojave 10.14.6. I tried to Force Quit the Windows 10 process in the macOS Activity Monitor. Although it disappeared from the Activity Monitor window, the Parallels window continued to show Win10 in Stopping mode and looping. I then tried to close Parallels again but it would not close. I tried to Force Quit Parallels from the macOS control window but there was no response. I then tried to restart the Mac but again no response. The only option left was a manual power down of the Mac, which I did. On manual restart of the Mac, I started Parallels, which then showed Win10 in the control window to be in a stopped state. On opening the VM, Windows went through its recovery boot and eventually started successfully.
Unfortunately there is an unresolved issue with Parallels to slowly start and end the Windows machine. It started with Mojave and Parallels 14. When Windows 10 does not shutdown, it often helps to deactivate the Hibernation setting in Windows.
Parallels 15.1.2 solves this issue for me - so many thanks to the Parallels team. (I use OSX Mojave 10.14.6)