Follow instructions below.
WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.
For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Make sure you back up the registry before you edit it. If you are running Windows NT, also update your Emergency Repair Disk (ERD).
When trying to connect to a published application, the published application will not launch. If you check the active processes in the Task Manager of the server, you will see Icast.exe as one of the active processes. Two minutes after launching the published application, the following error message may appear:
"[published_app_name] failed to start. The Citrix server is unable to process your request to start this published application at this time. Please try again later. If the problem persists, contact your administrator."
If you try to connect to the desktop (instead of the published application ), Wfshell.exe is not one of the active processes, so the session could lose device mapping settings; for example, clipboard mapping or sound mapping.
The problem may be that the registry entry for Cmstart.exe is missing or corrupt. To correct this problem, run Regedt32.exe and go to
HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsNTCurrentVersionWinlogon
AppSetup:Type = REG_SZ:
Data = USRLOGON.CMD,CMSTART.EXE
These values are the default values for the AppSetup entry. If Cmstart.exe is missing, add it manually and attempt to reconnect to the published application.
NOTE: Icast.exe (application launcher) waits for Wfshell.exe to complete before launching the initial program for the published application. If Cmstart.exe is not listed under AppSetup value, Wfshell.exe is not launched and Icast.exe will timeout (after two minutes by default), generating the error message mentioned above.