My dell system is running with UBUNTU 14.04. Till recently I didn't have a problem with the usb drives. Now when I insert a pendrive or a hard disk, it doesn't mount nor does it show in the file system. I have to go to disks and then mount it. If I do this and plug the drive into a Windows system, it shows that the drive is full and inaccessible.
I'm not sure I understand your last sentence but the first part sounds like auto-play is turned off. From the
Launcher
selectSystem Settings
thenDetails
andRemovable Media
. The screen below appears:When the last option is checked nothing will auto-play when inserted. Uncheck this option and set the others as desired depending on type of media.