I had a very weird Freezing of my Unity 6 Editor, after i wanted to open 2 unity 6 to cross-check some stuff, i do this very often so i suspected this must be something related to U6.
IN the end what happend was that my second unity 6 instance laoded the same editor Layout and complexly froze all the time (editor.tick) ans so on.
After i resetted the editor layout everyting was back to normal.
one of the error that came up was this: (GetStatus) Cannot get non-existing progress id 7.
Solution: reset your editor layout!