I bought a USB switch, an Aten US424. It works perfectly on every computer but not on my Raspberry Pi 3 with Retropie.
How can I solve or at least troubleshoot the issue?
[disclaimer] I don't have experience with retro-pi, but I will assume you have access to a terminal so you can run some commands to find out whats going on.
I have successfully used a similar USB switch out of the box.
first check if the USB device was detected using
if it not detected, it might be because of one of a few causes
sudo raspi-update to get the latest firmware updates and check again.
See this for details on what it does.
I'd recommend trying this on a spare microsd card / after backing up your card image to avoid messing up your existing setup in case something goes wrong.