So all of the sudden any USB drive won't allow me to write it. Read is great, but not when you're trying to write to a drive. Has anyone else experienced this? I've tried killall nautilus and killall nemo, as some other Linux variant users have suggested, but since they didn't work, I'm assuming that nautilus and nemo aren't part of MATE.
Any help is appreciated.
Hey 
How your devices are getting mounted ?
you can check it out running mount command inside a terminal and find out your device.
Let's see if it has read write