Post count: 480

Looks like file system corruption on your SD :-(

It could be possible to recover, have a look in this thread for some suggestions:

Otherwise you will have to start again with a new RetroPie setup, I moved to a USB install after my SD card kept corrupting, see this thread for instructions:

Another good thing to do is to make regular backups using Win32DiskImager:

Hope you can recover it :-)