You can't divide and conquer with an export to IDML, but you can with PDF, so see Adobe Community: File Crashing on Output - printing/PDF/other for how to quickly find a corrupt object or objects when making a PDF.
Thanks, great suggestion. Alas, absolutely no problem exporting the entire document as PDF.
That's interesting. perhaps this is a permissions problem on the folder where you are trying to save the IDML. Can you save it to the desktop?
How about a re-boot? Does that make a difference?
Funny you should ask. I did move it to the desktop to have an uncluttered space. Made no difference.
Finally I just made a new doc with the same specs, which took about 60 seconds, and cut and pasted content by spread. For 64 pages, that's 33 cut-and-pastes. Every 16 pages or so I exported as IDML, until it crashed, and I figured it was page 60, so I ungrouped objects on that page, reset images to allow text on top, and it was fine.
This was a document originally created in 1998 in QuarkXpress, translated by Q2ID and content and design overhauled in the last year, so I guess a cruft gremlin isn't something to really complain about. I was pleasantly surprised to see that cutting and pasting imported style sheets and correctly linked images (nice job Adobe!).