I had the same issue for several days. Every time I saved an Illustrator file, it would show this dialog box, create multiple files based on the artboards, and generate several .tmp files.
I tried upgrading and downgrading Illustrator multiple times, but nothing worked. Eventually, I realized it probably wasn't Illustrator itself, so I started looking into recently installed plugins, extensions, and possible Windows security conflicts.
After checking everything I had installed before the issue started, I found that I had recently installed ZXP Installer to add an extension. At first, I thought the extension was causing the problem, but it turned out that ZXP Installer itself was the culprit.
I uninstalled ZXP Installer, restarted my PC, and the problem was completely resolved. If you're experiencing the same issue, it's worth checking whether you have ZXP Installer installed or any extension or not anything prior the problem caused. Hope you find this helpfull.