I am unable to mount a USB drive (or SD card) to my system without root access. When I plug in a USB drive, it is visible in the left column of Nautilus, but when I click on it to open it, I receive the error message

Unable to mount 2.1 GB Filesystem
Error mounting: mount exited with exit code 1: helper failed with: mount: only root can mount /dev/sdb1 on /media/sdb1

I am able to mount the drive using sudo mount -w /dev/sdb1, but this causes problems for operations such as creating startup discs, which requires unmounting and remounting the drive.

I suspect this problem may be caused by the fact that when I upgraded from 11.10 to 12.04, I had an SD card plugged in. This caused the system to stall during later startups, as it could not find this drive. I remedied this by editing a line of /etc/fstab to read

/dev/sdb1         /media/sdb1  vfat  noauto          0  0

However, I am dual booting Ubuntu with Windows XP, and I have no problem mounting the C: drive of the Windows system without root access, so I feel that this is a problem related to the mount point rather than mounting in general.