I was working on a file for about 8 hours yesterday and was continuously saving it. The autosave was also triggering throughout my work.

However, when I started Illustrator today, the file is completely unchanged from its state on Monday. The thumbnail in the Home menu shows my progress from last night, but the file itself only contains the old data.

There have been no other save issue on that disk. I was able to save an XD file's progress in the same directory — at the same time — last night (shown in attachment) before shutting down my PC.

Windows 10 Pro Ver. 1909
Intel i7-8700k
16gb RAM