I have most of my tunes in FLAC on a NAS, all working fine.
I just connected an external hard drive filled with 1.8TB of AIFF files. It’s formatted exFAT. Plugged it into a USB3 port on the SonicTransporter, and mounted it using the drive mounter with the “read only” box checked. All good so far.
When I go into Roon Settings>Storage>add folder I can navigate to \storage\music\flac\usb and add the folder. It says “watching for files in real time”, however, no files are added, even if I hit force rescan.