Adobe unable to connect to DDE server
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.
