This has been covered lots of times before, but here you go...
1) Restart your comp
2) Go to your Auran folder
3) delete the file named "Assets.tdx" from the main directory
4) Open the 'Cache' folder
5) Delete the "Assests.bku" file from here
6) Restart the comp again
7) Load the game as normal (do NOT go in through CMP)
8) Wait... TRS needs to re-build its database and the time it takes will depend on a) How much custom content is installed and b) Your comp specs. To give you some idea my laptop takes about 10-15 minutes and has about 5GB of custom content whereas my desktop takes about 30 seconds but only has about 2GB and 5x the processing power.
Also be aware you will probably need to do this whenever you download something new off the DLS but not when you install from a CDP saved to your machine.
Hope that helps. :wave: