"Save As" is not working Illustrator

[Danelle5C98]

In the past 3 or so versions I have not been able to "save as" in Illustrator. "Save Copy" works but not "save as". I just updated to the new version and still have this issue only now I can't revert back to the previous versions. Any ideas how to fix this? 

[Monika Gause]

"Doesn't work" - can you please give us some detail?

Is there an error message?

File just not there?

Exactly where do you save? And which file format?