Mount error: mount failed: File exists

Question

I am unable to mount my USB:

$ mount /dev/sdb1 /mnt
mount: mount /dev/sdb1 on /mnt failed: File exists

What is the origin of this error and how do I mount my USB?

The partition /dev/sdb1 is not in /etc/fstab

I got the same error. [Here](https://pastebin.com/E7ZAkW6h) is my output. — Tom Hale, Nov 15 '17 at 11:31
Any news on this? I have the exact same issue but cannot find a solution. — Thorian93, Jul 17 '20 at 11:59
Only thing I found is the following post, but as far as I can see it is all about btrfs snapshots while I am only using a normal btrfs volume. https://unix.stackexchange.com/questions/537029/error-for-mount-system-call-failed-file-exists — Thorian93, Jul 17 '20 at 12:05
Does this answer your question? [Error for \`mount\`: \`system call failed: File exists.\`](https://unix.stackexchange.com/questions/537029/error-for-mount-system-call-failed-file-exists) — DanMan, Dec 31 '20 at 12:04

score 3 · Answer 1 · answered Dec 31 '16 at 11:52

3

the error means '/dev/sdb1' has already been mounted. in this case it is because you can't mount a filesystem to /mnt you have to specify a folder

su umount /dev/sdb1
cd /mnt
su mkdir usbstick
su mount  /dev/sdb1 /mnt/usbstick
exit

add it to fstab

/dev/sdb1 /mnt/usbstick fat32 noauto,users,rw,umask=0 0 0

change fat32 to whatever the filesystem on the stick is

answered Dec 31 '16 at 11:52

1

If the problem was that `/dev/sdb1` is already mounted, the error would be EBUSY, not EEXIST. You can always mount to `/mnt`, even if it has subdirectories; it would hide the subdirectories, but that wouldn't prevent the mounting. – Gilles 'SO- stop being evil' Dec 31 '16 at 20:27
1

there was no error specified by OP so you are guessing. and no you cannot always mount a fs to /mnt it depends on OS and sysadmin. letting any process mount a fs is a security hole. fstabs can be exploited. – μολὼν.λαβέ Jan 01 '17 at 00:04
@μολὼν.λαβέ I've posted my output as a comment on the question. It shows the error appearing when trying to mount on a freshly created directory. – Tom Hale Nov 15 '17 at 11:32
@Tom Hale what is your mount point? what permissions are you using? – μολὼν.λαβέ Nov 15 '17 at 23:55
1

@μολὼν.λαβέ As shown, the first mount point tried was existing, then a new directory was created as mountpoint, and that mount also failed (both via `sudo`). umask=0022. It seems a transitory error. I have a btrfs filesystem with errors. Rebooting fixed the mount issue. – Tom Hale Nov 16 '17 at 05:58
@Tom Hale that's very weird but the command should always work, from most *nix flavors to osx. if it doesn't i suspect the filesystem or driver is probably corrupt – μολὼν.λαβέ Nov 18 '17 at 18:47

1 Answers1