I have a problem with .xlsm files with Power Pivots in them "going corrupt". After working in a file and saving it, the next time I open it I often get a "Module Not Found" error. Then a "Can't find project or library" message when I "touch" anywhere inside the spreadsheet. That is a signal that excel is going to go in to a CRASH very soon. I have no idea if there is a way to salvage the file so I generally restore a backup as that works. Does anyone have any suggestions as to how to recover one of these files?