Partially read the file disappears with legacy format
In Illustrator 25.2.3, myself, my client, his colleague, and their client, all run into a nasty bug where some ai files will not open.
The dialog saying Illustrator could only partially read the file will appear and the file can't be recovered properly. Sometimes the file(s) can be opened on a second attempt, but, we have found that only by saving the files in Legacy format, will this bug disappear and the files are usable once again.
Kathryn Doner commented
YES PLEASE FIX THIS