Having the same or similar issue. This on 32bit W10.
Runs for a while OK. Then the Windows stops responding to the keyboard and mouse. Some things are still running, but you can't access them. Even the taskbar won't easily open. 90% hung.
However things sort of work sometimes if you wait a few seconds. Window that wouldn't close, move the mouse away, wait some seconds and then come back onto it and it responds. Seems to get worse the longer the screen is open. It's sort of partially running, but not responding to what you ask.
Have reinstalled the Parallels Tools. Did nothing. When I did this could not even click the 'restart' button to make it restart.
Had been working fine on the previous release for ages.
Right click at the top of the hidden taskbar (I have mine auto hiding), and you get the list with Apps & Features etc., showing, but click on any of the entries and nothing happens. Mow that is interesting, since when working normally, the entries highlight as the cursor moves over them. It's as if the core 'OS' is not actually receiving the data on where the cursor is from the Mac mouse. However it has to be receiving this the Apps & Features bar to launch. Unreliable in some way?.
Have managed once to launch Task Manager, and it doesn't show anything silly running. Less than 1% CPU. You can't drag windows around, or close them. But leave them for a while and you can come back and do so.
I did a full shutdown of Parallels and re-launched this, and it worked for a couple of hours OK, then hung again.
I had a separate 64bit W10 also installed. Since I hadn't launched it since the upgrade, I launched this and cancelled the Parallels tools installation, so it is running on the last release of tools. This has worked for a couple of slightly longer now, and is still working without issue. Suggests the problem is somewhere in the Tools?.