CDJ-850 Wont recognise my exported rekordbox tracks

0) Have you read the "READ ME FIRST" thread in its entirety AND TRIED THE SOLUTIONS THERE before posting: Yes, I swear it!

1) Operating System: Windows  7

2) OS Type: 32bit

3) rekordbox version: 3.1.0

4) Using LINK: No

4b) Using with CDJs: Yes (if yes, list them and their firmware version)

5) Flash drive system: FAT32

5a) Does the device have multiple partitions:Unsure

** 5b) If it's a flash drive, is it a U3 device*: Unsure (standard USB)

* 5c) With what utility did you format the device**: Windows

6) Have you scanned your files for errors:Yes

7) Have you scanned your drive for errors: Yes

8) Is rekordbox crashing at all: No

8b) If not crashing, are there any error messages: No

9) Are you able to repeat / reproduce the problem: Yes (happens everytime)

** 9a) If yes, can you do it consistently*: Yes

**10) Does the problem occur with one specific song: No (happens with all songs)*

 11) Any other notes regarding your setup only: NO

12) Provide as much detail of the issue here:

I have just purchased two CDJ-850's and a DJM 350. I have set up rekordbox and when I export my rekordbox files to a usb and plug it into the CDJ it says "library not responding". It work with regular, un analaysed rekordbox .mp3's. The cdj's also fully work with CD-R's. What can I try to resolve this issue? The USB is formatted to FAT32. It is a SanDisk Ultra USB 3.0 (32GB)

Any help would be apprechited.

Thanks