Sometimes applications need some adjustment when beeing used in a virtual environment, and dont always work as you want them too.
Now, Adobe has some guidelines for setting up Adobe products on RDS environments, which in this case already was implemented.
More on that here and here.
They also have a good reference on registry keys to be adjusted depending on the needed end result.
That can be found here
Having used this over a long time, I suddenly got some sites getting issues with Adobe Reader DC.
They all hadde the excact same config for Adobe, and never had any issues before.
Now suddenly the users got an error message when opening pdf or launching Adobe Reader DC directly. But the error just came the first time they launced pdf/software every day.
This started in April 2017, probably after some application updates on Adobe Reader.
Doing some troubleshooting on the basics, users profile etc solved nothing the problem was still there.
The next step was to look at the registry entries used for customizing Adobe Reader for terminal server, as I was sure the problem had to come from there.
After running through one and one of the entries used I found that the following registry entry was set to 0 in the Group Policy beeing applied on user logon:
Disabling this entry in group policy and doing a fresh logon, and the problem was gone.
Removing this setting, or just not putting it in there in the first place, and the problem goes away.
If using this setting, make sure it is set to 1 and not 0