Thread: Garmin DriveAssist 50 LM crashes and reboots at specific GPS locations

Do not format the SD card while it is in the Garmin.

then complains the sdcard needs formatting (to FAT) and asks me to format

Take it out first.
To many users wind up formatting the internal memory by mistake.
Unplug the Garmin from you PC or laptop first.
Then remove the SD card.

Like you were told by Butters:

Extract the RAR file directly onto a CLEAN small microSD formatted in FAT32:

There is no need to do anything else to the SD card........