El Capitan: Mount rejected

[GGGunrunner]

Hmm... I remember using Disk Arbitrator more than a year ago and it seemed to work w/o problems.

I'm now using it on 10.11.6 - mode "Read-only", Activated, and whenever I put a new USB stick (FAT32),
it writes "Mount failed: disk1s4"
The device does appear in DA's list of devices, but not in Finder (duh).

Is there anything can be done? I just want my USB stick mount as read-only for the purpose of stopping OSX putting Spotlight index files, Trashes, and all that crap... :)

[baszero]

Is there a solution to this? I also have this problem on macOS Ventura

[whosnorman]

++ on macOS Monterey