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I need to pull about 13GB worth of data off my Ubuntu 16.04 box. I'm running xfce via Recovery mode. When I plug in my usb drive it mounts as read-only. So I do:

$ df -h
...
/dev/sdb3 ... /media/user/backup_drive

$ sudo umount /dev/sdb3

$ sudo mount -o rw,users,umask=000 /dev/sdb3 /media/user

These commands succeed. If I cd into /media/user I can see the files on the drive. But if I try to modify the file system in any way I get a permissions denied error. For example:

$ cd /media/user
$ touch newfile
touch: cannot touch 'newfile': Read-only file system
$ sudo touch newfile
touch: cannot touch 'newfile': Read-only file system

If from the xfce desktop I right-click on the volume icon and select Properties I see this:

Owner: 99
Access: Read & Write
Group: 99
Access: Read & Write
Others: Read only

Is it the "Others" permissions that's causing me grief? Any suggestions would be much appreciated.

RobertJoseph
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    Please have a look at these links, one of them might help or at least explain what is happening, https://askubuntu.com/questions/884562/unable-to-access-sd-card/884622#884622 ; https://askubuntu.com/questions/144852/cant-format-my-usb-drive-i-have-already-tried-with-mkdosfs-and-gparted/933035#933035 – sudodus Jul 29 '17 at 15:37
  • If you check the instructions in those links you'd see that I am doing the exact same things here. – RobertJoseph Jul 29 '17 at 15:39
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    Then the problem might be that the drive itself is read-only. Try the tips listed in the paragraph 'The drive is read-only' in the second link (in my previous comment). – sudodus Jul 29 '17 at 15:43
  • I really appreciate your help but the drive is definitely not read only. I use this drive all the time across several different machines/OSs. Ubuntu is the only OS that is giving me permissions issues. – RobertJoseph Jul 29 '17 at 15:44
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    Well, then I suggest that you solve the acute problem with another [live] OS. Later on we can start debugging the problem with Ubuntu. (It could be that the drive or the USB system is disturbed by something.) – sudodus Jul 29 '17 at 15:46
  • What file system is there in /dev/sdb3? FAT32 or NTFS or some other file system? – sudodus Jul 29 '17 at 15:55
  • Your Xubuntu unfortunately remembers a problem with your USB-stick - so you have to give the USB-stick an other UUID number! You can use Gparted for this, under Partition the next to last option is New UUID. This saved a couble of my sticks.. – Ken Mollerup Jul 29 '17 at 16:16
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    Use my pathlld tool https://github.com/waltinator/pathlld.git - Bash script to answer "Why can't I read/write that file?" – waltinator Jul 29 '17 at 16:20
  • What/who is the owner 99? What is the output of grep 99 /etc/group ? How was owner 99 created? I do not recognize it as one of Ubuntu's standard users or groups. How was the file system of /dev/sdb3 in the external drive created? – sudodus Jul 29 '17 at 17:27

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