I cannot believe this issue has not been corrected. I'm so overly frustrated with this and am dumbfounded by the amount of people that have a similar issue. If one can not SAVE their work, why is this not at the top of the list for issues to be repaired? I just recently got the latest Illustrator software installed (25.3.1, 64 Bit) on my home PC thanks to getting a new job and needing to work from home. I updated my perfectly working CC version for this. EVERY SINGLE file I open or create, CAN NOT be saved. It sits there and sits there until the error appears, or it just crashes the system. I have spent the past "6 hours" trying every single repair option that has been posted about this subject on multiple forums. I have uninstalled and reinstalled the software multiple times, and NOTHING is fixing this issue. I can not do any form of work with this software now.
Seperate Issue: Exporting a JPEG from an illustator file turns the image ALL BLACK. The jpeg image appears for a split second then turns completly black. What the hell is going on with your software Adobe? I have tried this on multiple computers, and multiple software versions and its all useless...
Do you save your work locally or on a server/ in a cloud folder?
With problems like this it is always best to first get the files copied to the local harddisk, edit, save them and copy them back.
Did you als check if turning of the Preferences > File Handling > File Save Options > Save in Background and Preferences > File Handling > Files > Open File Open an Save Times on Slow Networks makes a difference?