We regularly use RiR. Once in a while in the past 2 months, we had the following issue (several RiR/Rhino WIP versions, tested on 2 machines).
In Revit 2019/2020, Rhinoceros tab shows up, then when I try opening GH, just before the GH window should show up, Revit abruptly crashes. After restarting Revit+RiR, the issue persists. If this happens, often opening GH from Rhino WIP crashes Rhino in a very similar way. Either of the following solves this problem:
(1) delete the content of C:\Users%USERNAME%\AppData\Roaming\Grasshopper\AutoSave
(2) do the above, then delete all files (not subfolders) in C:\Users%USERNAME%\AppData\Roaming\Grasshopper (note that this deletes some user settings for all GH version)
I wonder why is this happening? I assume there is a file that RiR can’t load from the above folder. Besides RiR, we regularly use Rhino 6+GH, often simultaneously with Revit+RiR.