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I'm trying to use a USB drive (FAT32) on my laptop running Ubuntu 14.04, but the permissions are messed up and I don't understand them well enough to fix it.

Running ls -l in /mnt shows 

drwxrwxrwx 3 root root 16384 Dec 31  1969 usb SanDisk_Ultra_4C530001080718105394-0:0-part1

I'm pretty sure this indicates I've set all users to have all permissions (this is not the final configuration I'd like, but bear with me).

Despite this, I cannot copy files to the drive. When in Nautilus I check the Permissions tab under Properties (for the directory /mnt/usb-SanDisk_Ultra_4C530001080718105394-0:0-part1), it says that only root has write permissions, and that since root is the owner I cannot change that. Using sudo chmod, sudo chown, and sudo chattr all fail, which I don't quite understand but I think is related to the file system being FAT32. (This is a drive I'd like to use between multiple computers and operating systems, so I believe that I should stick with the file system.)

The entry in fstab reads

/dev/disk/by-id/usb-SanDisk_Ultra_4C530001080718105394-0:0-part1 /mnt/usb-SanDisk_Ultra_4C530001080718105394-0:0-part1 auto user,umask=001,dmask=000,nosuid,nodev,nofail,noauto,comment=x-gvfs-show,rw 0 0

I manually added the options user, umask, and dmask, and changed x-gvfs-show to comment=x-gvfs-show to fix an error that prevented the drive from mounting (a solution I found on these forums). Otherwise, all of the options were as I found them. I had already reformatted and repartitioned the drive multiple times before making any of these modifications. I'm out of ideas, and frustrated that it's so difficult to just use a thumb drive in a "plug and play" fashion, could anybody help?

EDIT: This question is not a duplicate, as the methods described in the answers to the other question do not fix my problem when I try them (see comments). In fact, even before trying it seems like the problem is different, since mounting manually or through fstab should function similarly and I had already laid out my fstab configuration, indicating the uniqueness of this problem.

Ben
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    Please read http://askubuntu.com/questions/11840/how-do-i-use-chmod-on-an-ntfs-or-fat32-partition – Rinzwind Jun 30 '16 at 18:58
  • Forgive my ignorance, but shouldn't the mount permissions already be set by fstab? The mount options in the post you're linking to are all options I've already set in fstab, as can be seen in my original post. – Ben Jun 30 '16 at 19:45
  • Just in case, I followed those instructions. I unmounted with sudo umount usb-SanDisk_Ultra_4C530001080718105394-0\:0-part1/ and remounted with sudo mount -t vfat -o rw,auto,user,umask=011 /dev/sdc1 ./usb-SanDisk_Ultra_4C530001080718105394-0\:0-part1/. I still cannot copy files, and ls -l now returns drwxrw-rw- 3 root root 16384 Dec 31 1969 usb-SanDisk_Ultra_4C530001080718105394-0:0-part1. – Ben Jun 30 '16 at 20:27
  • I have no idea what's going on, but just to see what's going on, I'd temporarily comment out the fstab entry, plug the drive in and see what device it is associated with using ls /dev/sd*. Then sudo mkdir /mnt/work sudo mount /dev/sdx /mnt/work (where x is the device letter.) Then, as root, you should be able to read and write anything on the drive. If that works then work on the fstab entry. If it doesn't work, then analyze the external drive for hardware or formatting errors. – Joe Jul 10 '16 at 05:32
  • Cont: Alternatively (with the fstab entry still commented out), if you have dolphin or a similar file manager installed, the drive may just appear in Places when it is plugged in. Then, just clicking on it will usually mount it with normal user read/write access. Dolphin will create its own mount point. – Joe Jul 10 '16 at 05:39

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