Sometimes you found that when you installing some MSI package on TS/XenApp Server, The installation is not completing and you getting one Pop-Up "Windows installer Coordinator" which seems continuously running.
To resolve this create and set the following dword value to 0:
HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Terminal Services\TSAppSrv\TSMSI\Enable
If this value is not present then create it your self.
The issue will be resolved.
You can find more information in this link