Error:
Citrix offline plug-in Error
An error occurred while starting your application.  Please contact your help desk.

You receive the above error when launching a streamed application.

I experienced the issue after someone changed a username within Active Directory.

You may also receive the below error within the event log

Error:
Launch of application from the location failed and the last error message was: An error occurred while starting your application.  Please contact your help desk.

To resolve, logon to each Citrix server where the streamed app is assigned to and open a command prompt.

Next, type: cd “c:\program files\citrix\streaming client\” and press enter

Type radecache /flushall

Try launching apps again. If this does not work, run the same command on the profiler server and try again.