Sorry about the trouble you are facing. I would like to know if the steps suggested above by @Monika Gause worked for you? If not, I would request you to share a few more details like:
Exact OS & version of Illustrator
Where are you saving the files (Network Drive/ System HDD/ Shared Folder on System/ External HDD)?
When did this start happening? Are there any recent changes made to your system? For example, any antivirus, system updates, or web extensions installed recently.
Also, you may try the following steps one by one and let us know how it goes:
Rename the CEP folder to "CEP.old" from the following location: Windows: C:\Program Files (x86)\Common Files\Adobe Mac: /Library/Application Support/Adobe
If that doesn't help, rename the extensions folder to "extensions.old" from the following location: Windows: C:\Program Files\Common Files\Adobe\UXP MAC: /Library/Application Support/Adobe/UXP