SW2025 Simulation: "Storage for study is not found."

I just lost a great deal of work in an assembly with several simulation studies defined. I opened one of the parts to edit geometry. On closing the part I got this message repeated for most of the studies. Three of eight studies are left, so I have most of the setup, but now I'm afraid to keep working and losing studies again. 

How can one avoid this problem in Solidworks 2025? 
[I am only working outside of Solidworks 2020 because it has certain hard limits on problem size. 2025 does not have the same limits, but is slower, less stable, and apparently still has some serious bugs.]