There's no difference in fuctionality between paid and free versions.

There are two things worth trying, if you haven't already closed and lost the file. The first is to export to .idml, open that and see if you can save it with a new name: Remove minor corruption by exporting

The second is riskier as it depends on ID's amazing file recovery after a crash. If the method above fails you haven't got a lot to lose, though, so here here's the next thing I would try:

Force Quit Indesign. See Replace Your Preferences and use the manual method to replace the InDesign Defaults and InDesign SavedData files (and while you're at it, make a backup copy of the InDesign Recovery folder). Also see Adobe Forums: InDesign crashes at startup and delete the additional files in John's post. If you need to delete or copy hidden files and don't know how to access them, see Access hidden user library files | Mac OS 10.7 Lion

When all that is done, restart InDesign. With luck, autorecovery will open the file again with not much missing and you can try to save it.

The "why" is hard to know. I'm glad it worked out.  Are you working across a network with a file? That's one major place where things can go bad.

Many organizations use a network workflow, but the networks need to be rock solid. Much safer to keep the files you are writing and saving on the local hard drive if you can, then copy back to the network when you are done.

Bryan Holland wrote:

I usually save to Dropbox to work on file from either iMac or air

But this time: desktop.

I hope you are moving the file from the dropbox (yeah, that's a network, and you're relying on an iffy internet connection) onto your Mac or PC before opening for editing, saving locally, then moving the new version back to the dropbox. Working directly from the dropbox is not a safe thing to do.

???? If the file you'd overwritten had been the one in the dropbox, how would that have helped you?

I'm not saying don't store them there, I'm saying don't write directly to them in the dropbox from ID.

Does it do the version for you, or are you saving new versions yourself?

I have to say I personally found Dropbox to be very clunky and annoying when I tried it, so I've not given it much of a chance. But I stand by my opinion that working on files over the internet is asking for trouble.

Ah. I guess I completely misunderstand Dropbox. Thanks for the clarification.

Thanks, I'm feeling really old this week and in need of plenty of help.