I must be missing a step somewhere ... I have done exactly as you have described above, yet I never get the setup wizard. I have deleted the docker and started over from scratch, but the results are the same. What else can I try?
I would try :
1. Remove the docker + image from the Unraid Web UI Docker's page (Remove, and choose yes to remove also the image).
2. I will delete the /mnt/user/appdata/unifi-video and /mnt/user/appdata/unifi-video-logs
3. I will add the docker, then i'll just start/stop it.
4. I will create the file "system.properties" with only 1 line, is_default=true
5. I will start the VM and check the web UI of UniFi-Video.
Note: Make sure the file you create is named "system.properties", with no other extension (i.e: system.propreties.txt)...
Did all of the above and it still just redirects to /login when I browse to the web UI. At this point I am out of ideas ... I may be able to try on a different unraid box. Is it not possible to make the docker already have the system.properties file as default? Just curious.