CDJ 2000 not seeing USB

Hi all, appreciate any help on this. Will try and be clear

ISSUE: 2000s not showing either of my USB drives (not just showing the contents folder but not showing the USB drive at all when navigating on the decks). 

USB Drives - 64gb Sandisk Extreme Go 3.1 and a 32gb Sandisk 

Laptop - Macbook Pro 2015 running Catalina

Both have been formatted in disk utility - MS DOS FAT (FAT32) and the playlists exported through the sync manager in Rekordbox. 

Am unable (it's greyed out) to partition the 64gb. 

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The extreme go usb plays fine when going in to my buddy's laptop when using the ddj-800 with all relevant griid/cues etc on the tracks. The smaller sandisk was previously working on cdjs (another dj gave me his spare last night to try and get me going). 

After exporting the drive, was not coming up on the CDJs. 

Is there something i am missing when exporting?