Rekordbox and HDD Format Issue

Hi,

I'm using a Seagate 1TB portable drive to store my music on and have been for the past year or so with no issues whatsoever. I have just come to use rekordbox and all of a sudden my HDD is in the incorrect format?

I cannot access the drive in rekordbox but can listen to the music fine by clicking into it in my macbooks file explorer. The error basically says that the drive is in an unsupported format and needs to be FAT12, FAT16 or FAT32 but I haven't done anything to change the settings of it, I'm not even aware how to.

The only thing that I have changed recently is that I have purchased a new usb stick which has a larger capacity so I was going to transfer my music onto that, I'm not sure how but could that have affected my HDD? There's no other reason I can think of why my hard drive would suddenly be unsupported and the data can't be corrupted because I can still access and play the music.

The bizarre thing is that I can even import the music off the drive into rekordbox but it will not let me click on it in the browse section, that's where the error message comes up saying it's unsupported.

Any help would be greatly appreciated.

Thanks