OS? Version of ID? How much free disk space do you have on your hard drive?
Thanks for your patience!
iMac with Mac OS 10.6.8
I am unsure how to find out what free memory I have left; but info on the Hard Drive says:
Capacity 249.72 GB
Available 161.6 GB
Used 88.12 GB on disc
OK, that should be plenty of space for swap files, so you've got some other problem. Try rebooting your mac, then open ID and your file, and immediately export to .idml and resave that as a new .indd. See Remove minor corruption by exporting