The fix for this issue is now available in the latest update of InDesign – that is, InDesign 15.0.2.
Please update your InDesign application to get this fix.
Adobe InDesign team
An error occurred while saving the commentAnonymous commented
I have the most up to date version of indesign, just made a new file (the first time ive used this program in about a year) literally the first new file I made this happened about 3 hours into working. Seems like this has been an issue since 2010. Whats the point of this program existing if you can't save your work?