...like it did with Insider Preview Build 15042. Same remedy: Reboot the VM containing build 15046 with reinstalled Parallel Tools; this causes BSOD, but system enters Repair Mode after an iteration or so. Now select Advanced Options | Troubleshoot | Advanced Options | Startup Settings | Restart, and subsequently choose "Enable low-resolution video". The system duly boots in lo-res, but the proper resolution kicks in as soon as the logon screen appears; after this, the system will run stably. If you enable the Boot option "Base video" using msconfig.exe, you can restart the system at leasure from then on--with Parallel Tools installed.
So based on your advice I changed the screen resolution from retina to scaled before doing the upgrade...and finally it all worked fine! Thanks for the post.
