I can't open PDF or AI files by drag/drop or right click open, please help?

Hi everyone,

For the past week I have been unable to drag and drop (to open) any PDF or ai files into my Adobe Illustrator (or PDF into Acrobat). I receive a lot of my work over email and am use to dragging it from the received email in outlook and hovering it over the selected and appropriate icon on my dock, then letting go for it to instantly open. This is now not possible. Also just right clicking the file while its in the email and selecting the correct application wont work either. It just opens the selected application but no file.

A common message that sometimes appears is "Illustrator is not currently open" (same for acrobat) which is strange as they are definitely open. I'm currently having to save everything that gets emailed to me, even if its just a PDF with some information I need to quickly read.

Is there anyway to fix this? It all worked absolutely fine before and meant I could work at a decent speed.

I have no clue, and can't find anything online. Many thanks for any help!

I use a Mac