# Permission denied on USB drive **URL:** https://forum.syncthing.net/t/permission-denied-on-usb-drive/19769 **Category:** Support **Created:** [February 8, 2023, 7:28pm UTC](https://forum.syncthing.net/t/permission-denied-on-usb-drive/19769 "2023-02-08T19:28:12Z") **Posts on this page:** 1 **Showing post:** 3
### Author: ![gadget](https://forum.syncthing.net/letter_avatar_proxy/v4/letter/g/dec6dc/32.png) [@gadget](https://forum.syncthing.net/u/gadget) #### Post date: [February 9, 2023, 12:40am UTC](https://forum.syncthing.net/t/permission-denied-on-usb-drive/19769/3 "2023-02-09T00:40:00Z")
> [@InteXX](#): > > I just provisioned a new Bullseye OS on my RPi 3, installed So I’m guessing it’s the latest major release of Raspberry Pi OS? If so, it means it’s [Debian](https://debian.org/) for the Linux distribution and [LXDE](https://lxde.org/) for the desktop environment. > [@](#): > > Side note: the NTFS formatting is a requirement, as the drive serves as part of a disaster recovery plan for a Windows environment. It used to be that NTFS was the only viable option in a mixed OS environment that included Windows, but [Dokany](https://github.com/dokan-dev/dokany) and other tools make it practical to use ext2/3/4 and btrfs on external storage (in particular, btrfs’ architecture, per-block checksums, plus other features are very useful on large volumes that contain lots of small files). > [@](#): > > Some relevant info: > > - The drive is auto-mounted somehow by the OS; `/etc/fstab` is pretty much empty LXDE, the default desktop environment for Raspberry Pi OS, uses GTK and other tools from GNOME. PCManFM talks to [gvfsd](https://en.wikipedia.org/wiki/GVfs) which manages device mounts at the user level while `/etc/fstab` and [autofs](https://kernel.org/doc/html/latest/filesystems/autofs.html) handle the system level. > [@](#): > > - I ran `sudo chown -R admin:admin /media/pi/D6986D4D986D2CE5` on the drive, which took at least an hour to complete Note that because NTFS doesn’t natively support Unix-style metadata, `chown` only lasts as long as the volume stays mounted. As soon as it’s unmounted and remounted again it’ll be “owned” by `pi`, or whoever is currently logged onto the graphical desktop environment at the time the USB drive is plugged in. > [@](#): > > - After the `chown` command completed, PCManFM still indicates `pi` as the owner in permissions > - Read/write access to the drive is set to `Anyone` (see screen shot) > > ![image](https://forum-uploads.syncthingcdn.net/original/2X/3/3e70e8a2fafcc09d61b7cf406603639384d8b59c.png) In the screenshot above, PCManFM is displaying the permissions for `/media/pi`, which is the parent directory for removable media that’s inserted by user `pi`. Each removable media gets its own subdirectory (if a volume label is available, it’s used by default, otherwise it could be the UUID, system device name or something else). The command `sudo chown -R admin:admin /media/pi/D6986D4D986D2CE5` changed the ownership for `/media/pi/D6986D4D986D2CE5` rather than for `/media/pi`, so PCManFM is correct. > [@](#): > > The odd thing is that I had this working at one time, under an older distribution on an RPi 4. In fact, that’s how the files got there in the first place. I can’t for the life of me figure out what’s gone wrong here. > > I seem to recall something about having to manually configure the auto-mount under that older OS (it was a few years ago that I put the setup together), and then somewhere along the line having been pleasantly surprised at an apparently new Raspbian in-built feature that automatically mounts external USB drives. If this is the cost, though, I suppose I can do without (assuming the mounting process is somehow related to the error). Auto-mounting of USB drives in a desktop environment has been available in Raspbian/Raspberry PI OS since the early days, but support for NTFS required extra work (the `ntfs-3g` package often isn’t installed by default and built-in kernel support didn’t [happen until 2021](https://arstechnica.com/gadgets/2021/08/paragon-is-working-to-get-its-ntfs3-filesystem-into-the-linux-kernel/) (`ntfs3` module starting with the 5.15 Linux kernel)). > [@](#): > > I’m at a loss here, friends. Do you have any ideas? How can I get Syncthing to work with my drive? Expanding on what @Nummer378 has already covered… Since you have Syncthing running under `admin:admin`, one option is to log onto the desktop as user `admin` before plugging in the 10TB USB drive so that the auto-mount will automatically set the ownership to `admin:admin`. Another option is to manually unmount and then temporarily override the ownership during the mount like so (replace `1234` with the actual UID/GID assigned to your `admin` user): ```plaintext umount -v /media/pi/D6986D4D986D2CE5 mount -v -type ntfs-3g -o uid=1234,gid=1234 /dev/sda1 /mnt/sda1 ``` The downside to the `mount` command above is that it assumes that your 10TB USB drive is always at device `/dev/sda`. A better way is to use the volume label, device ID, UUID or other more consistent identifier. Because `D6986D4D986D2CE5` is too random looking to be a volume label, I’m guessing it might be a serial number or some other auto-assignment. If you don’t already know which it is, issue the following command: ```plaintext find /dev/disk -name D6986D4D986D2CE5 ``` If it’s the partition ID, modify the mount command like so: ```plaintext mount -v -type ntfs-3g -o uid=1234,gid=1234 /dev/disk/by-partuuid/D6986D4D986D2CE5 /mnt/10TB ``` If it’s the volume label: ```plaintext mount -v -type ntfs-3g -o uid=1234,gid=1234 /dev/disk/by-partlabel/D6986D4D986D2CE5 /mnt/10TB ``` (As root, create the mount point with `mkdir /mnt/10TB`. Don’t worry about the default directory ownership because it’ll be temporarily overridden each time by the `mount` command.) Optionally, for a `/etc/fstab` entry (adjust as needed for your `/dev/disk` pathname), add… ```plaintext /dev/disk/by-partlabel/D6986D4D986D2CE5 /mnt/10TB ntfs-3g uid=1234,gid=1234 0 0 ``` … then your `mount` command can be shorted to… ```plaintext mount -v /mnt/10TB ``` It’s simple, clean, and portable so it won’t break between OS upgrades. --- _[View the full topic](https://forum.syncthing.net/t/permission-denied-on-usb-drive/19769)._