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I have a 16 GB flash drive formatted as FAT. When I plug the flash drive into my Dell Laptop running Ubuntu 14.04, I can read and write with no problem, but when I plug the same flash drive into my Dell Tower running Ubuntu 16.04, it sets up as read only. Below are results for report file system disk space usage (df -Th) and list directory contents showing permissions (ls -la) at each location. I am logged in as user at both locations.

Why are the permissions showing up different at each location? What can I do to set the flash drive to read and write on the Dell Tower running Ubuntu 16.04?

I have tried sudo chmod 666 /dev/sdc1 but that has no effect on permissions. I have also tried sudo chmod 666 /media/user/EBC2-93C8 same thing.

Dell Laptop Ubuntu 14.04

$ df -Th
/dev/sdb1      vfat       16G   72K   16G   1% /media/user/EBC2-93C8

$ ls -la /media/user
drwx------  3 user user 8192 Jan 16 16:09 EBC2-93C8

Dell Tower Ubuntu 16.04

$ df -Th
/dev/sdc1      vfat       16G   80K   16G   1% /media/user/EBC2-93C8

$ ls -la /media/user
drwxr-xr-x  3 user user  8192 Dec 31  1969 EBC2-93C8

I tried the solution posted at

How do I change permissions on a FAT32 formatted drive?

Unmount the flash drive from nautilus, but do not remove it.

sudo mkdir /media/flash
sudo mount /dev/sdb1 /media/flash -o dmask=000,fmask=111

It did not work right away. I had to unplug the flash drive and plug it in again. Now it works! Will this fix persist even after I reboot?

Thanks!

Follow-up notes......

the media directory now has two sub directories: user and flash.

after I rebooted the Dell Tower Ubuntu 16.04 machine and plugged in the flash drive, it appeared in the user folder.

but it appears read/write privileges have returned.

sudo fdisk -l

Disk /dev/sdc: 15.1 GiB, 16225665024 bytes, 31690752 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x9c767207

Device     Boot Start      End  Sectors  Size Id Type
/dev/sdc1  *     5968 31690751 31684784 15.1G  c W95 FAT32 (LBA)

df -Th

/dev/sdc1      vfat       16G  152K   16G   1% /media/user/EBC2-93C8

ls -la

total 16
drwxr-x---+ 3 root root 4096 Jan 16 17:39 .
drwxr-xr-x  4 root root 4096 Jan 16 17:20 ..
drwxr-xr-x  3 user user 8192 Jan 16 17:43 EBC2-93C8

what's the little plus sign doing there?

also, I tried several variations of chmod.

sudo chmod 666 /dev/sdc1
sudo chmod 600 /dev/sdc1
sudo chmod 666 /media/user/EBC2-93C8
sudo chmod 600 /media/user/EBC2-93C8

none seem to work. oh well.

fossfreedom
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beampoweramp
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  • If you're still unsuccessful, could you please [edit] your question to include the output of id -u; id -g, ls -lan "/media/$USER", and cat /proc/mounts on both systems with the removable storage device connected and mounted? Thanks. – David Foerster Jan 17 '18 at 09:25
  • I ran the commands as you asked, but there's a lot of output. Could I narrow it down to just the sdc listings, or do you want everything? – beampoweramp Jan 17 '18 at 21:45
  • If you know which entry (or entries) from /proc/mounts refer to the file system in question, I'm happy for the pre-filtering. :-) – David Foerster Jan 18 '18 at 03:20

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