error message There is no disk in drive e every time I try to open a pdf file in Acrobat Reader DC

Whenever I try to open or scan to a pdf file I get this error message There is no disk in drive e every time I try to open a pdf file in Acrobat Reader DC.  I can hit one of the three buttons cancel, try again, continue and it disappears and everything will work properly.  It is just a nuisance since it comes up every time.