During upgrade, following error shows up: "Agent installations are missing, please contact your System Administrator or our Supportservice"
This error message is present on the main RA webpage, in the space where "Download Agent Setup" menu and button used to be.
Somehow the agent images were not copied over to the proper directories on the NAC.
RA 6.x after upgrade
The NAC holds the agent installation files in 2 places: RA_HOME/scripts and RA_HOME/webapps/nolio-app/apps
Verify that the nolio_agent* files (as present in the ./agents dir on the 6.4 installation image) are present in both locations.
If not, copy them over.