shortcut command S to save in illustrator, my adobe acrobat automatically opens it as a PDF

Hi John,

I would like to know if the steps suggested above worked for you, or the issue still persists.

Kindly update the discussion if you need further assistance with it.

Thanks,

Srishti

Are you saying that the saved document is being saved with the suffix .pdf or is it that your files are being saved as .ai files but when you double-click on their icon they open in Acrobat? If the latter is the case then the fix for a Mac (you said that "Command-S"—a Mac command—was the issue) is to click on the icon in the desktop or within a finder window using Command-i and getting a Get Info window. Within that window in the area called "Open with:" choose your version of Illustrator and then click on "Change All". After that Acrobat will no longer open files with the .ai extension. 

reset your preferences,  http://helpx.adobe.com/illustrator/using/setting-preferences.html

[moved from Adobe Creative Cloud to Illustrator]