@luke -- what's the Mac version of fsck (command-line filesystem check, Windows' version is chkdsk) and did you run it? I've 'fixed' improperly-unmounted USB thumb drives with that command.

On Linux, where 'sdx' is your SSD, "fsck -a sdx" (no quotes!) followed by a punch of the ENTER key, will do good things, if it's just a corrupt filesystem. Corrupt filesystems are not mountable and won't show up in eg Thunar. (Sorry, I'm an XFCE kinda guy.) In Linux Mint (which I use) and probably other Ubuntu-based Linux derivatives, you have to run fsck as root, so prepend 'sudo' to that command for those.