TNS410 usb playback issue

[isusdfr]

I have a issue with playback of my USB mp3,s in my TNS410 unit in my toyota. Even though I have about 8 pages of music files I can only see the files on the first page, the up and down arrows are grey out and cannot be pressed.
my folders are laid out by band name but i can only see the first page folders starting with A..
It doesnt matter if i select playlist or artist or album, song etc it will only ever show the first page.

Any ideas on why this is happening?
If i select randoom play it will play any of the 600 odd songs that I have. I had a quick look through the manual and the only thing i can think it may be is that it states that it can use usb sticks with a max storage size of 4 GB and i just realise that i have a 16gb stick in there, would that be it???

UPDATE: i formatted the usb and then put all the songs back without folders so all 450 songs in the root directory. Took it out the car to test and it worked fine I could scroll down all my songs, could scroll for albums etc. That was yesterday, went for a drive tonight and the problem has come back, can only see on page of song, albums etc, down and up arrows are greyed out

any ideas???

 

[alfie67]

It would be helpful to know, are the arrows only grayed out while the car is being driven? My Toyota GPS does not allow the driver to select certain functions while on the move (safety issue).