Adobe unable to connect to DDE server

[Eniac8764013]

Users will submit tickets for not being able to open PDF files or the Adobe reader DC application. Remote into their PC and find errors saying "Adobe cannot connect to DDE server." and multiple instances of the Acrord32.exe process running. As soon as you kill the all acrord32 processes you can open pdfs and Adobe again. However, the issue will return in a couple of days. I've tried everything I've found on the Adobe forums in regards to fixing this issue including:

-Running a repair on Adobe Reader DC.

-Uninstalling with Adobe Cleaning Tool and reinstalling fresh from Adobe site.

-Updating to newest version.

-Editing registry to disable Adobe welcome screen.

-Verified a different registry key was set to correct value.

-Rebuilt user profile.

-Turned off open in protected mode.

This issue has been incredibly difficult to replicate as it's pretty inconsistent. This isn't a global issue in that everyone is experiencing it but a wide range of users are having issues opening PDFs. These machines are on Win7 x86/x64.

The one test I can't be sure about was the disabling the antivirus (TrendMicro) as it would need to be left unloaded on a workstation on the domain for at least a few days.

[Eniac8764013]

As far as I can tell, this is only an issue when 'Start Reader in Protected Mode' is disabled. The reason we have to set 'Start in Protected Mode' to disabled is due to some PDF's causing conflict with Protected Mode. It will throw an error that says Protected Mode couldn't start due to compatibility issues or it will just render grey in IE. In addition, the only way I can find to contact support for Adobe Reader DC is on these community forums; is there a way to get ahold of somebody since there hasn't been any fixes on the Adobe forums that work to fix this?