My slightly educated guess would be a conflict between the Popup and/or Notify client ports and the Citrix plugin ports?
The seemingly simplest solution would be to change the default port for either the Pharos client/s or the Citrix plugin.
Hopefully you have a development environment where you can test either solution before making a global change to either...
I agree with Michael Wineke. We have seen this kind of issue before when two applications try to take control of the same resource. That resource is usually a networking port. The first app grabs the port and typically works and the second application or service fails to start and throws an error on startup or attempted use of the port. The Pharos Uniprint client ports are
In the Uniprint documentation area (here), we have a diagram showing just about all the Uniprint ports and the directions of communications.
According to the Citrix documentation (I found online), the Offline Plugin only uses
None of these seem to be in conflict. I'd look in the Windows event viewer and any log files you can find to see what specific error messages are being thrown and what is happening when this issue occurs. Also, try different methods of installation order and if it happens when printing, try different ways of printing (with and w/o Pharos client getting involved). If you are unable to resolve the issue to your satisfaction, please enter a Pharos Support ticket to at least get another look.