The number of files should not be a problem. My XT shuffles through about 1800 song tracks (25 GB) on the SDcard and plays without issues.

See if you have the same problem using the BT dongle with another source for an hour.

Or try another SDcard.

If you are using a playlist, try no list, or a ...

Thanks jfheath for your response and advice!

I don't know what version of bluetooth is on my Zumo, I cannot figure out how to check that in the settings.
The bluetooth dongle is only connected to my Zumo, not to my phone.
I usually try to turn off bluetooth and wifi on my phone during rides, to ...

Hello all,
I'm having somewhat similar issues.
I have a Zumo XT with MP3 files on an SD card and I use a cheap bluetooth dongle with S Plug earbuds.
The turn-by-turn navigation works fine (mostly) but after 30 minutes or so the music slows down and then stops altogether.
Sometimes turning the unit ...