Looks like doing an upgrade from 16.10 to 17.04 killed my Parallels guest. I now get "failed to connect to lvmetad" error upon boot. Thankfully it's a throw away test VM, however I would warn anyone else considering an in-place upgrade.
Hello Traveloguy, unfortunately, ubuntu 17 will not work in Parallels Desktop 12. Please refer this article http://kb.parallels.com/123893 We will forward this feature request to our development team. Hopefully, it will be added to a future release of Parallels Desktop.