I installed 12.10 a while ago, but I am now experiencing problems with USB devices. At first I had problems copying files to a flash disk. I was told that there is not enough space on the disk, but the amount of files amounted to a fraction of the capacity of the device. I formatted the flash drive with gparted and copied the files. Then I ejected the device and the moment I pulled out the device I got an error message about not being able to write to the disk. At first I thought I pulled the disk to quickly, but repeating the exercise a few times discovered that this happened even when waiting ten minutes before removing the drive after ejecting it. If I re-insert the disk, I get an error message that the drive could not be mounted. Since then I have had similar problems when writing files to an external hard drive. I'm not getting the same problem on my other PC with Ubuntu 11.10. I'm desperate at this stage as I can't write files to external device. Ubuntu 12.10 keeps on corrupting the file system.
I know it's probably too late to help you but maybe others can find a helpful explanation here for a workaround to this issue http://itsfoss.com/how-to-format-a-sd-card-or-usb-drive-in-ubuntu-12-10/