I am running windows 7 on a dell desktop. PDF files freeze shortly after opening or tryiong to print. Only the PDF freezes all other functions remain normal. I can close the PDF. I have an HP officejet pro 8600

Are you opening that PDF in Adobe Reader?  What version?

Try to disable Protected Mode [Edit | Preferences | Security (Enhanced)].

Hi Duncan,

Please confirm if you Are using Acrobat.com online services or Acrobat software?

Regards,

Rahul