[josechaney]

It took a good 30 minutes or so to upload everything (AAC format @ 256Kbps).

Mine took a really long time to complete. Probably longer than 30 minutes. All mp3 files in my case.

 

[josechaney]

What size USB flash drive are you using?

I think mine was 16GB. I also think that's the max capacity of the Honda drive.

 

[josechaney]

Original poster here with an update...
My system reported there was a software update ready to be installed, so I did that and out of curiousity I tried uploading to My Honda Music. It now works! All the previous suggestions in this thread were unsuccessful, so apparently there was something in the old software preventing file uploads.

Excellent!