I had an issue with PDF files not opening from email attachments. We ended up having to disable Protected Mode in Acrobat Reader. This can be achieved using the following steps.
- Open Acrobat Reader, got Edit | Preferences (or press Ctrl+K).
- Navigate to Security (Enhanced) in the Categories list.
- Unselect "Enable Protected Mode at startup".
- Close both Acrobat Reader and Outlook.
- Open Outlook and try opening the PDF file. Should open without any issues.
There is also a Group Policy ADMX file you can download from Adobe to manage this using a GPO. Sorry, I don't have the link of hand.
Regards,
Hugh
