I am having a recurring problem of static simulation studies disappearing mid-use.

I'm working in an assembly file with multiple studies painstakingly created, some of them completely solved, and in the middle of working on the file it seems to revert back to a version from HOURS earlier - some study tabs have simply disappeared. I save the file every 10 minutes or so - it reverts far prior to the latest save. These are 100% local files, on my C: drive, there is no networking issue going on. I *think* it's happening when I switch to the model view out of the study tabs, but I'm not sure.

My 3D card is on the approved list. Closing out and reopening doesn't help. Restarting the computer doesn't help. The studies are no longer being referenced in the assembly file. I can even go into my simulation files folder and see the CWR's there for the studies that have disappeared. Can anyone help???

This has occurred on multiple occasions now, and I have lost several full days' work. These are not simple analyses I'm performing and it is driving me to explore other software packages because this is untenable.