I got the following answer when chatting with Adobe Technical Support:
There is already a bug logged for the same.
Our engineering team is working on it. Will come up with a solution soon.
Titti Backstrom: So the problem will be fixed in a coming update of InDesign?
It's already been escalated.
this issue is still happening to me- i have the most updated version of indesign. i need a solution.
Me too! This is outrageous!
I encountered the problem today.
Open a .indd document I've been working on for the past week. Text, tables, photos in .psd, vector art in .ai, spot PMS color.
Then today, I drop in a few characters of a different font, hit "Save" and get the dialogue box, "File cannot be saved. Disc space is low. Try quitting InDesign to free up disk space."
I'm trying this fix mentioned above. Fingers crossed.
Mac OS 10.12.6
2TB disk space