Update: Several readers wrote to say that this is a well known problem that exists on Windows machines as well as Macs. For example, Ronald Guest states: "If you search the MS Knowledge Base, you can find a half dozen articles about thevarious possible causes. We've been burned by this several times.A shortage of memory is only one of the possible causes. Another is opening a document that requires conversion of some of the graphics. This Red X of Death can happen frequently when exchanging documents with Windows users, since most of the graphics must be converted."