XDJ RX2 USB not reading

I've owned my XDJ RX2 for 1 year now and I have had no problems, I have been using the same USB's the whole time i've owned them but now my decks aren't reading my USB's properly. At first they wouldn't read them at all but now it reads it intermittently. When it does read the USB the tracks won't load and sometimes they done show up at all. 

My USB is a sandisk ultra flair 3.0. 

Is there anyway to resolve this issue, i've had no problems with them until now