I don't see any issues when I first open PhD or if I go to File | Open Project... I tried it with recent projects and with projects made with older version of PhD (v10).

One thing that happened when opening a project from v11 is that I got the below message that stayed at 0% for a long time:



I eventually clicked Postpone and the project became available, but there were many missing photos from that project and I closed PhD to start over. I was then unable to launch PhD again and saw that it was still running in Task Manager even the the window was gone.

I don't know if this weird background operation might be related to the issue you're seeing, but try opening a different project and see if that's successful.