Pages just deleted!! Help!

Question

I have a large document, 78 pages, that I have been working on. All of a sudden, I scrolled to the end and many of my pages are now blank. The page is still there but all of my work is deleted. I did a "save as" of the document, closed it, and opened my original and the pages are still blank. I have no idea what happened. It is about 1/3 of my pages, randomly thoughout the document, but mostly at the end. Any ideas? Any way to restore my document to the one I had 30 minutes ago??

Answer 1

why do files get corrupt?
I would answer somewhat differently than Peter. While it's true that neutrinos or random subatomic particles can cause corruption, that path is extremely rare, and there are mechanisms that try to detect those bit-errors (checksums).
The primary cause of corruption is software bugs. Somehow the document acquires some state that doesn't make sense. For instance, say, paragraph is supposed to have 200 characters but really only has 100, so in reading the 200 characters for the paragraph InDesign reads the next paragraph as well and everything is off-by-one (this is a contrived example and not really how it works).
These bugs typically arise when a programmer has screwed up and didn't realize the effect some unanticipated case can produce. Sometimes the effects are visible to us, sometimes they aren't. Sometimes one little damaged piece will cause other assumptions to fail and a document to get further damaged. Sometimes the damage may be isolated and not affect anything.
You yourself encountered one:
I got an error message that said indesign isn't working and needs to shut down.
This is InDesign detecting something is inconsistent. If you poke around at the ProtectiveShutdownLog (see http://kb2.adobe.com/cps/329/329853.html), you can find out why it thought so -- or a one-line potentially-inscrutable summary thereof, maybe.
What do I need to do to make sure this doesn't happen again?
Well, Peter's certainly right that you should keep backups.
The other thing, of course, is to try to keep careful track of anything you do that causes a clear manifestation of a bug, and to document them and report such bugs to Adobe and get them fixed (at http://adobe.com/go/support or http://adobe.com/go/wish). This is, of course, fairly challenging, and to some extent a problem that does not scale easily. Still, if everyone did it, especially for bugs of the reproducible variety, it would be much better for everyone. This is true of all software, of course.