Generic Volume preventing me from trying to Stanby?

I just want to standby my computer, but this pops up.
"The device driver for the 'Generic volume' device is preventing the machine from entering standby. Please close all applications and try again. If the problem persists, you may need to update this driver."

Firstly, I've tried closing all applications, but it still pops up the same message. Secondly, I have no idea how to update this driver thing?

Thanks for all help :)