Since a few days I am having severe issues with anything that's on the (internal) SD card on my Nexus S.

When I mount my phone into a computer, all is fine. Everything is recognized, and files are where they should be. Also file browser apps on my phone recognize everything, and I can play music when I tap the files individually.

But music apps will not recognize any music anymore. Both the stock player and Winamp don't see any music.

Also, my Gallery app crashes when I tap any album, and it shows a wrong number of pictures. However, I can access my photo album by using the Camera app (since Jelly Bean it's possible to go straight into the gallery app with the camera app), so that's a possible workaround.

What's even more strange is that when I go to settings-->storage, it will nicely tell me there's 4GB of pictures and 3GB of music on my (internal) SD card. So it does see there there is something.

I've already tried rebooting a few times, to no avail.