Hi Todd,
This is a limitation in Inventor at the moment. We have heard this request for many years but we don't have a good solution unfortunately. There are multiple technical challenges on enabling Auto-Save in Inventor. First, Inventor has one Undo stream for one session, not per document. When you open several files, you can undo all the way back to zero documents. When you save a file, the Undo stream may be chopped off. Also, if you automatically save multiple files, the Undo stream could be interrupted leading to more instability.
Another issue is related to file referencing and associativity. Inventor assembly and drawing reference model files extensively. When Auto-Save kicked in, should all related files be saved or only the active document be saved? The user will need to make a decision on the spot. Arbitrarily saving the files can lead to corruption. There are custom add-ins enabling Auto-Save. But, I have seen corrupted files caused by such tools.
Like I mentioned earlier, we don't have a good solution at the moment.
Many thanks!
Johnson Shiue (johnson.shiue@autodesk.com)
Software Test Engineer