I opened that up too. I can see what some things are but not others. My guess is that I needed to turn off morphblender to get the file open but I wouldn’t know what I was looking at to turn anything off.
I did do some testing tonight. Basically rebuilt the morph part of the rig and did incremental saves all along the way.
The problem seems to arrive when I try and create a new group with the sliders. I have no idea why. That’s was after about 18 incremental saves when I found that one. Very strange.
I still have a few things to rebuild after last night but it’s not crazy amounts.
What I might do just for safety is that every time I shut down a file I’m going to turn morphbuilder off and just turn it on again when I start to animate.