Windows XP SP3 2GB and Illustrator CS 13.0.2
While working on a number of Illustrator images (x3), a new one was created by copying an EPS vector image from MSWord as a background template. A further 10 layers were added whilst working on the new image file. There was a prompt that the document had been modified and may not be editable in other versions. "Show this message again" was cleared (as he usually does on a MAC). Later while flicking between the open image files, when he attempted to return to the new image file it appeared to have closed. Illustrator had not crashed, it was possible to continue working on the other files and there is nothing in the event logs On re-opening the file it had been flattened (converted).
Others have experienced similar when using Illustrator, where files appear to close themselves.
Any ideas ?
Word EPS is evil. You may in fact have copied over a damaged data structure that makes all things go haywire and forces AI into flattening everything (since it thinks it is still an EPS and EPS can't hold transparencies and layers...). A safer way to work would be to print to PDF, then place the PDF into the AI. this way everything stays self-contained and should not affect AI's internal workings.