Thank you for the reply...
Originally I followed the following article sent to me by Garmin Support using the Mac section - [Only registered and activated users can see links. ]
Therefore I had formatted it to MS-DOS (FAT).

Since, I have formatted it using RMPrepUSB to FAT32 and I left all other settings default so I assume that was correct. I have factory reset the unit by powering on with finger held on bottom right of screen.

The first hurdle is that it doesn't get found in Garmin Express. I know the computer sees the device because when I connect it to the computer the SatNav shows the connected to computer display and in the Device Manager on the computer a 'MTP USB Device' appears so it is definitely connected. I've tried another cable but get the same so I know it's not the cable.
I've tried connecting the SatNav to Garmin Express on a Mac computer and then just in case there was something wrong I have now switched to a Windows 10 computer so it can't be the computer.
I've tried with the SD Card in the device and out of the device.

Any idea what I can try? Maybe it's to do with the formatting?



Spoiler: here
[Only registered and activated users can see links. ]

[Only registered and activated users can see links. ]

[Only registered and activated users can see links. ]