I had a customer call me about an issue back in February; They would plug in a USB flash drive filled with music, and only 255 songs would be displayed on the StarLink infotainment screen of their 2015 Subaru Forester. This sounded strange to me, so I asked to get together so I could take a look and see what the issue was. Sure enough, I got to the customer's house and the infotainment screen was only showing 255 songs when there were literally thousands on his USB flash drive.
I did some research, and buried deep in the Forester's owner's manual was an interesting set of rules governing how to store music on your flash drive for use on your Subaru's StarLink system.
Connectable USB Storage Device
Mass storage class USB memory can be connected. USB storage devices that can be are accompanied by the following restrictions.
- Maximum directory layers: 8 layers (including the ROOT)
- Maximum number of files in a folder: 255
- Maximum number of folders: 512 (including the ROOT)
- Maximum number of files on the device: 130,560
- Maximum capacity: 16 GB or less
The issue was the customer had all his music in one folder, and that was more than the system could handle. Once he went back and reorganized his music into different folders for each band and album (the way iTunes organizes music by default) everything played exactly as it should.
I'm sure these restrictions apply to more than just the 2015 Forester, and I'll be updating this post as I encounter this situation in the future.