Reader in Sandbox mode can’t read/write to registry after Outlook 365 MAPI gets loaded using SendMail – open a file in Reader and then go to File > Send File > Attach to Email. And thus, any changes to preferences are not retained.
You can manually tweak the registry as a workaround. Follow the steps below. Before you do this, read the possible side effects it may have on Acrobat Reader.
Possible side effects:
- Acrobat Reader may hang.
- After closing the draft mail window, you may not be able to open another PDF by double-clicking it.