Good Lord, you lot must be tone deaf. MP3 went out with the Ark. It was only ever to solve storage problems, at the expense of sound quality, and now we have USB sticks with hundreds of gigabytes of space there is zero need to encode to such a dreadful sounding format.

All.
No point in burning discs - my cd player is u/s hence fitting the Umno interface!
So:-
My big mem stick with the now-mp3 converted tracks on doesn't work in the Umno - for elimination, the original smaller stick still does (this had tracks on that were already on my pc not in itunes and correct format).
There were some folders there - have removed, so now it is just tracks, but the device just doesn't seem to like it.

How big is the "Big" one? Some devices only recognise up to a certain size. I know this Disco Sport can read my 64 gig one but the 2011 L322 could only read up to 32GB ones

Little one is a 4 gig, big one is 32 gig, the unmo does up to 64 gig.
Weegie (John) rang me this afternoon with an idea so watch this space!
J 2007 Vogue TDV8 with 255/55/20's fitted

Success !!!

After John's advice about folders and number of tracks I set about making up some folders named 1-10 (other names are available!). Then placed no more than 99 tracks in each one. Deleted all not required folders. Plays like a dream!

Blasted shame that the track names didn't come over with the swap off itunes/mp3 format change. But now have plenty music to **** off the kids on the way to Brands Hatch tomorrow morning

Thanks to all. Appreciated. 2007 Vogue TDV8 with 255/55/20's fitted

The elderly sometimes have their uses.  John
2008 Stornoway Grey 3.6 Tdv8 Vogue
2005 TD6 Java Black Vogue - Written off!!
GAP iiD BT
2003 Discovery TD5 Auto, Nanocom Evolution - gone to a new home!
MasseyFerguson 152 - No electronics!! - Sold

Indeed you can teach these kids a thing or two! 2007 Vogue TDV8 with 255/55/20's fitted

As I said the music is easily extractable but the file structure not so much!

Hey ho at least you have the stuff to listen to. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
KIA E-Niro 4+
2010 LR D4 Commercial 2.7 TDV6

USB sticks can have two different formatting systems, FAT32 and NTFS. The second is newer, better and can handle larger file sizes. However, some older things don't like them. I think anything that accepts a USB will read FAT32. I believe the max file size (for a single file) is 4GB. Check what the old, small stick and the new, big stick are using. That might be the difference. (Check properties or get info and it should tell you.)

Mzplcg, yes MP3 were made to solve storage issues and they certainly sound dire at low bite rates. However, while I may have a tin ear, I find 256 and 320 just fine for in car listening.