I feel stupid to even mention this....

I never have seen folders work in my Ram 1500 truck, nor this 2019 Prius. Considering that the Prius came with a CD player, Toyota being stuck at always being five to eight years behind with infotainment really doesn't give me hope. Hell, the one dealership I asked was totally dumbfounded at my question of what Prius I would need to get to get satellite radio - hell, I had satellite radio capability (and subscribed to it) on my 2015 base-model Ram pickup truck. Toyota does not move into the future well at all.

 

From the USB screen Select "Browse". The first screen should display the play lists available for the currently selected category. Radio button category labels for genre, songs, artists & albums are listed horizontally near to top of this screen (if you do not see the "Folders" category, scroll left or right using the arrows). Selecting "Folders" will display the mp3 folders in the USB flash memory. Selecting the desired folder should automatically start playing the first song in that folder. Hit return twice to get back to the top USB screen. From that point, Entune should play tracks from the selected folder in alphabetical sequence (or randomly, if shuffle is selected) and you can sequence to the next song using the steering wheel control up/down ring buttons. Volume is controlled by the +/- ring buttons, and next source (radio, bluetooth etc) is sequenced with the center "mode" button on the steering wheel.

I have a 11.6 inch display, but your display should be similar, if not the same.

 

No. I had exactly the same problem. I didn't see it either because it was scrolled off-screen. You have to use the left or right arrow (I forget which) to bring it into view.

 

Sorry to hear that. I find it hard to believe that they would provide a USB port that plays music but will not sort by folder. That's pretty basic.

Digital format will sound pretty much the same regardless of the source, so I doubt that Amazon Music will make that much of a difference. The exceptions to this are sources that enhance their own digital files. Some internet radio station do this. I use studio software to enhance my own tracks to increase fidelity and stereo separation. It makes a huge difference in the sound quality but you have to know what you're doing for it to be effective.

One simple thing you can try that might help improve sound quality is to adjust front-rear balance further to the rear. When you do this, you will likely have to increase volume to compensate.

 

As you have seen confirmed in this thread, the Prius does NOT recognize folders on a flash drive. Which is especially annoying given that it DOES recognize folders on a CD that you have burned.

What I did was retag all my MP3 files to put in the genres in which I wanted to categorize them. If you already have them in folders, you can select all the files in a folder and change the genre for all of them at once.

While I was at it, I made sure that both the "Contributing artists" and "Album artist" tags were set for each MP3 file. I think "Album artist" is the one that the Prius displays while it is playing a track.

 

Some Prius models DO recognize folds. See my earlier comment with photo showing browse menu.

I have a 2018 Prius Four Premium with the 10spkr JBL Entune system. It recognizes mp3 folders. Chris Wolfgram has a 2019 Prius LE that has a sound system that does not recognize mp3 folders. He states above that the folder radio button is not shown in the browse menu.

I am not sure which sound systems recognize folders and which do not, but I suspect that you have to either have a later version of Entune for it or a high tech premium option.