I've been waiting to ride in the dunes. Interesting track. When you jump on the track in the VR world, you get the feeling that you are in the desert among the dunes. Set time to afternoon, then it looks great! The sand has some great features, too. There is something strange about physics though, not sure what it is. Maybe car slides to much in the sand. Very promising! Keep up the good work. It would be great to be able to drive freely along the dune. PS: Do the tires really squeak even on the sand?
Btw can you try to install using Content Manager > Upload from file and select the the_dunes_1.1.zip file?
I tried and I didn't get any error after uploading.
You can also try to reload Content Manager, open Content > Tracks and select The Dunes.
Then try to Reload and Drive.
If you need more help please contact me.
Send me your structure folder from assettocorsa/content/tracks/the_dunes_1.1 so I can check if some file is missing from the installation.