I have a very similar problem happening. It's been happening for about 2 months, not sure I can pinpoint a date or reason. Windows 10, running on MBAir with Parallels 10, which I recently upgraded to 11, hoping this would resolve the issue, which it has not.
I have followed all procedures above, including disabling Windows Defender and Antivirus. Also specifically I followed Guna's instructions through to step 4. I had problems with step 4 as the run command didn't find any installers in the temp folder. So at this stage I ran the PTAgent as administrator.
So If I run it as regular user (which is an administrator anyway) the installer reports failure around 10-15%, but if I run it as Administrator the installer gets to 60%, changes screen size, goes to 67% and pauses there for a few seconds and then reports the failure with a window requiring reboot. The result dow not seem to differ whether AV and Defender are off or on.
I'm getting rather tired of this. All for getting Dynamic Resolution and speakers back.