Can you post the data file [zipped?] or PM it to me. It's hard to comment without more substantive detail.

the autosave file is always in the same file as the model. To find out where your autosave default is open a new SU document and just hit save, then look which directory it is saving too, your file is prob there.

@gaieus said: Hi Dan, Check the warning box under Preferences > General > Scenes and styles. You will get those annoying popups that ask if you want to change, save as new or do nothing... Thanks Gai