I just bourght a new pc and installed RF2 on an blank new hard drive, after wizard I chose the 2nd recommendation, and it started to sync with workshop contents. I encountered some errors saying that "blah blah blah requires unknown base mod". And when it's done, basically all of the purchased dlc contents along with many workshop contents were missing, even though they were not the ones showing error messages earlier. I can see them in the \Steam\steamapps\common\rFactor 2\Installed\Vehicles and locations folders, but not in the game. In fact, every time I run RF2 the missing contents creat a new one in the folders, but they just don't show up in the game. Delete and reinstall or validation don't work. Any idea what should I do?
Try this. Go to your Steam Workshop and unsubscribe to all the series. Open rF2. Go to the Content tab and uninstall all the Mods (not the cars). Close rF2. Close Steam (i'm not sure if it's necessary, but just in case). Open Steam and wait if downloads something. Open rF2.