Ninja V SSD no longer shows up on Desktop

For a few days now my Ninja V no longer mounts to the Desktop, but it is available in the sidebar if I open a Finder window. In my Finder Preferences everything is checked under "Show these items on desktop:" Unchecking and rechecking seems to make no difference. I had an SD card recently with this same behavior and reformatting it fixed the issue. It doesn't fix the Ninja V drive though. The Ninja V SSD is reformatted (with secure format) every time I use it in the Ninja V, as per Atomos recommendations. The format of the drive is ExFAT.

I am using OS 10.14.6 Mojave since the super-fast copy/past/save functions of Quicktime 7 are invaluable to me.

Am I missing something? Hopefully so, as the only other thing would be "planned obsolescence" slowly creeping in.

I have two Ninja Vs, a Shogun 7 and several AtomX/Angelbird SSDs, always formatted in the Atomos recorder. I use the Atomos USB-C dock, plugged directly into a USB-C/Thunderbolt port on the machine:  www.bhphotovideo.com/c/product/1435429-R...owered_docking.html/

On Mojave, Catalina and Big Sur, I recollect infrequently seeing a failure to mount issue where it doesn't show up, but it wasn't isolated to the desktop. I don't think it's unique to the Ninja V because I sometimes (rarely) see it on SD cards using the internal reader. 

It seems when I reboot the machine it usually goes away. I don't know what causes it and on my machine it doesn't happen very often.

If you are using a hub of any type, try plugging the dock directly into a USB-C port.

You can also try re-launching Finder via OPT+right click>Relaunch on the icon in the dock. Sometimes that will fix it without rebooting.

Here are some other suggestions, inc'l iCloud Drive settings:  macreports.com/desktop-icons-are-missing-or-disappeared-on-mac/

Unfortunately rebooting and relaunching the Finder doesn't work. The Atomos dock is plugged directly into the computer (I have a 2013 Mac Pro), but I removed it and plugged it into a different USB port, directly into the computer. Still no go. I tried removing the Amazon extension USB cable and that still didn't help. If I use Disk Utility and format it as Mac OS Extended, it'll show up on the Desktop. But for some reason Atomos HATES that and insists on reformtting it to ExFAT. Once that happens it stops showing up on the Desktop. Even if I reformat it to ExFAT using Disk Utility, it goes away. I wonder if Apple is trying to force me to get a newer version of Mac OS.

My co-worker has the same SSD cards, two Ninja Vs and his always mount OK on a 2019 MacBook Pro 15 running Mojave. I don't think this has anything to do with Atomos or FCP. However to simplify things I would try mounting them after a reboot and with FCP, Compressor and all other NLE-type software shut down.

Doing a Google search I see people discussing terminal commands which affect visibility of hard drives on the Mac desktop. There are also Finder plist files that might affect this. E.g: apple.stackexchange.com/questions/230283...desktop-via-terminal

Other discussion about missing desktop icons: macreports.com/desktop-icons-are-missing-or-disappeared-on-mac/

You might examine what kernel extensions you have. Use this terminal command:

kextstat | grep -v com.apple

On Big Sur and later, the command is:

kmutil inspect | grep -v com.apple

The Terminal commands didn't help. I even booted into SAFE MODE and the drive was nowhere to be seen... except in Disk Utility. But it wouldn't mount when I told Disk Utility to mount it. Might have been a SAFE MODE thing. While in SAFE MODE, I deleted the Finder preferences and rebooted into the normal DANGEROUS MODE. The drive showed up. Yay! Of course I had to reorganize some icons on my desktop but that's OK. The last page you linked to had the tip of deleting the Finder prefs as its last options. So thanks for that!

Holding down COMMAND + OPTION + P + R until you hear a 2nd chime on startup clears out prefs and offending cache so that might have worked as well without having to go into safe boot mode. (Tip provided as a tip to future others having similar problems after searching here for an answer.)
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Your Mac’s parameter random-access memory (PRAM - said as 'P-ram') stores important information such as the type and identity of your macOS system drive, the presence of any other internal drives, the number and type of connected devices, screen resolution, and speaker volume.

www.alphr.com/mac-startup-options/
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Also... I'd never rely on OSX's formatting a drive to ExFat on an SSD that's to be used in an Atomos unit but instead rely on Atomos's internal version of ExFat formatting. Although they're theoretically the same it's the Atomos that's doing the I/O (read/write) operations of your once-in-a-lifetime capture and it'd be unfortunate if there was a hiccup in being able to mount/read the drive like something you experienced.

(Had a shooter that had a similar problem. HIS Atomos recognized the footage but he couldn't transfer it. Piped the video from his Atomos and captured it on mine (Atomos formatted) as a live transfer then saved the files. Reformatted his drive in his Atomos then copied back the files. When he got back to his editing bay he could now read mount the drive & read the files fine.