While launching Symantec Installation Manager (SIM) 7.6x the following message is displayed on Windows Server 2012:
'Desktop Experience' feature is enabled on this system. This feature is not supported on Symantec Installation Manager version 7.6x. Disable the 'Desktop Experience' feature using Server Manager then restart the system and launch Symantec Installation Manager.
ITMS 7.x
SIM does not support 'Desktop Experience' feature on Windows Server 2012 R2. For better user experience, SIM will detect if this feature is enable on the machine and show the above message.
Disable this feature:
Note: in some cases you may need to uninstall as well "Ink and Handwriting Services" and "Media Foundation" features.