After upgrading to 16.0 I can't mount usb disk as normal user

fperal · September 30, 2026, 5:06pm

I had my usb backup disk in fstab as

UUID=1c6ac58e-f4ad-4d45-b41a-aacbe8d18390 /mnt/backup  ext4 noauto,users,defaults

after upgrading to 16.0 i can’t mount the drive from the removable devices icon in the bar (plasma 6), so I commented the line (even rebooted after it because it didn’t work) and tried to mount it hoping it will mount in run/media/fernando as it happens with, for instance a pendrive, but it keeps failing.

i can mount and umount the disk as root with

mount /dev/sdc1 /mnt/backup
umount /mnt/backup

The log show

2026-09-30T18:51:28.880293+02:00 andromeda kernel: [ T4538] EXT4-fs (sdc1): mounted filesystem 1c6ac58e-f4ad-4d45-b41a-aacbe8d18390 r/w with ordered data mode. Quota mode: none.
2026-09-30T18:51:51.201005+02:00 andromeda systemd[1]: mnt-backup.mount: Deactivated successfully.

Then i can mount and umount as normal user from a konsole with

fernando@andromeda:~> udisksctl mount -b /dev/sdc1
^C
fernando@andromeda:~> ^C
fernando@andromeda:~> ^C
fernando@andromeda:~> ^C
fernando@andromeda:~> c


 c: command not found
fernando@andromeda:~> 
fernando@andromeda:~> 
fernando@andromeda:~> udisksctl mount -b /dev/sdc1
Mounted /dev/sdc1 at /run/media/fernando/1c6ac58e-f4ad-4d45-b41a-aacbe8d18390

fernando@andromeda:~> udisksctl unmount -b /dev/sdc1
Unmounted /dev/sdc1.

but trying to mount the disk from the removable media icon in the panel returns “you are not authorized to mount this device”

what can be happening?

deano_ferrari · October 6, 2026, 12:20am

Examine sudo journalctl -f when trying to mount the disk from the removable devices icon. That might help determine the underlying issue here.

fperal · October 6, 2026, 7:04am

it happen with two disk, both toshiba, both ext4

Oct 06 08:52:31 andromeda kernel: sd 6:0:0:0: [sdc] Synchronizing SCSI cache
Oct 06 08:52:31 andromeda kernel: sd 6:0:0:0: [sdc] Synchronize Cache(10) failed: Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
Oct 06 08:52:48 andromeda kernel: usb 1-2: new high-speed USB device number 8 using xhci_hcd
Oct 06 08:52:48 andromeda kernel: usb 1-2: New USB device found, idVendor=0480, idProduct=a202, bcdDevice= 3.15
Oct 06 08:52:48 andromeda kernel: usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Oct 06 08:52:48 andromeda kernel: usb 1-2: Product: External USB 3.0
Oct 06 08:52:48 andromeda kernel: usb 1-2: Manufacturer: TOSHIBA
Oct 06 08:52:48 andromeda kernel: usb 1-2: SerialNumber: 2015*******367F
Oct 06 08:52:48 andromeda kernel: usb-storage 1-2:1.0: USB Mass Storage device detected
Oct 06 08:52:48 andromeda kernel: scsi host6: usb-storage 1-2:1.0
Oct 06 08:52:48 andromeda mtp-probe[49649]: checking bus 1, device 8: "/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/usb1/1-2"
Oct 06 08:52:48 andromeda mtp-probe[49649]: bus: 1, device: 8 was not an MTP device
Oct 06 08:52:48 andromeda mtp-probe[49650]: checking bus 1, device 8: "/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/usb1/1-2"
Oct 06 08:52:48 andromeda mtp-probe[49650]: bus: 1, device: 8 was not an MTP device

Oct 06 08:52:54 andromeda kernel: scsi 6:0:0:0: Direct-Access     TOSHIBA  External USB 3.0 5438 PQ: 0 ANSI: 6
Oct 06 08:52:54 andromeda kernel: sd 6:0:0:0: Attached scsi generic sg2 type 0
Oct 06 08:52:54 andromeda kernel: sd 6:0:0:0: [sdc] 3907029164 512-byte logical blocks: (2.00 TB/1.82 TiB)
Oct 06 08:52:54 andromeda kernel: sd 6:0:0:0: [sdc] Write Protect is off
Oct 06 08:52:54 andromeda kernel: sd 6:0:0:0: [sdc] Mode Sense: 23 00 00 00
Oct 06 08:52:54 andromeda kernel: sd 6:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Oct 06 08:52:54 andromeda kernel:  sdc: sdc1
Oct 06 08:52:54 andromeda kernel: sd 6:0:0:0: [sdc] Attached SCSI disk
Oct 06 08:52:54 andromeda udisksd[2652]: Error probing device: Error sending ATA command IDENTIFY DEVICE to '/dev/sdc': Unexpected sense data returned:
                                         0000: 00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00    ................
                                         0010: 00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00    ................
                                          (g-io-error-quark, 0)
Oct 06 08:52:54 andromeda ksystemstats[3101]: org.kde.libksysguard.systemstats: Tried to add SensorObject with id "sdc" to container "disk" that already contains an object with that ID, ignoring.
Oct 06 08:52:54 andromeda systemd[1]: Started dbus-:1.2-org.kde.kded.smart@5.service.
Oct 06 08:53:05 andromeda systemd[1]: dbus-:1.2-org.kde.kded.smart@5.service: Deactivated successfully.

the log is almost the same for both disk.

it may seem that there is some error in the drive, but they are two different drives with two different cables and they was being monted by the icon in kde without error before upgrading the system to 16.0, moreover, if i mount it as root

 # mount /dev/sdc1 /mnt/backup

it mounts ok

Oct 06 08:58:30 andromeda kernel: EXT4-fs (sdc1): mounted filesystem 1c6ac58e-f4ad-4d45-b41a-aacbe8d18390 r/w with ordered data mode. Quota mode: none.

moreover, i can mount as normal user from console

~> udisksctl mount -b /dev/sdc1
Mounted /dev/sdc1 at /run/media/fernando/1c6ac58e-f4ad-4d45-b41a-aacbe8d18390

whit this log

Oct 06 09:03:10 andromeda kernel: EXT4-fs (sdc1): mounted filesystem 1c6ac58e-f4ad-4d45-b41a-aacbe8d18390 r/w with ordered data mode. Quota mode: none.
Oct 06 09:03:10 andromeda udisksd[2652]: Mounted /dev/sdc1 at /run/media/fernando/1c6ac58e-f4ad-4d45-b41a-aacbe8d18390 on behalf of uid 1001

deano_ferrari · October 6, 2026, 8:00am

Just to clarify further - run sudo journalctl -f first , then then click the disk in the Plasma removable-devices icon and wait for the ‘not authorized’ error. Hopefully that will help with understanding why Plasma fails with the authorization.

fperal · October 9, 2026, 12:19pm

I plug the disk in the usb


Oct 09 14:10:02 andromeda kernel: usb 1-2: new high-speed USB device number 4 using xhci_hcd
Oct 09 14:10:02 andromeda kernel: usb 1-2: New USB device found, idVendor=0480, idProduct=a202, bcdDevice= 3.15
Oct 09 14:10:02 andromeda kernel: usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Oct 09 14:10:02 andromeda kernel: usb 1-2: Product: External USB 3.0
Oct 09 14:10:02 andromeda kernel: usb 1-2: Manufacturer: TOSHIBA
Oct 09 14:10:02 andromeda kernel: usb 1-2: SerialNumber: 20150511002367F
Oct 09 14:10:02 andromeda kernel: usb-storage 1-2:1.0: USB Mass Storage device detected
Oct 09 14:10:02 andromeda kernel: scsi host6: usb-storage 1-2:1.0
Oct 09 14:10:02 andromeda mtp-probe[5095]: checking bus 1, device 4: "/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/usb1/1-2"
Oct 09 14:10:02 andromeda mtp-probe[5095]: bus: 1, device: 4 was not an MTP device
Oct 09 14:10:02 andromeda mtp-probe[5096]: checking bus 1, device 4: "/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/usb1/1-2"
Oct 09 14:10:02 andromeda mtp-probe[5096]: bus: 1, device: 4 was not an MTP device
Oct 09 14:10:08 andromeda kernel: scsi 6:0:0:0: Direct-Access     TOSHIBA  External USB 3.0 5438 PQ: 0 ANSI: 6
Oct 09 14:10:08 andromeda kernel: sd 6:0:0:0: Attached scsi generic sg2 type 0
Oct 09 14:10:08 andromeda kernel: sd 6:0:0:0: [sdc] 3907029164 512-byte logical blocks: (2.00 TB/1.82 TiB)
Oct 09 14:10:08 andromeda kernel: sd 6:0:0:0: [sdc] Write Protect is off
Oct 09 14:10:08 andromeda kernel: sd 6:0:0:0: [sdc] Mode Sense: 23 00 00 00
Oct 09 14:10:08 andromeda kernel: sd 6:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Oct 09 14:10:08 andromeda kernel:  sdc: sdc1
Oct 09 14:10:08 andromeda kernel: sd 6:0:0:0: [sdc] Attached SCSI disk
Oct 09 14:10:09 andromeda udisksd[2646]: Error probing device: Error sending ATA command IDENTIFY DEVICE to '/dev/sdc': Unexpected sense data returned:
                                         0000: 00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00    ................
                                         0010: 00 00 00 00  00 00 00 00  00 00 00 00  00 00 00 00    ................
                                          (g-io-error-quark, 0)
Oct 09 14:10:09 andromeda ksystemstats[3071]: org.kde.libksysguard.systemstats: Tried to add SensorObject with id "sdc" to container "disk" that already contains an object with that ID, ignoring.
Oct 09 14:10:09 andromeda systemd[1]: Started dbus-:1.2-org.kde.kded.smart@2.service.

Ten i click in the bar in the icon and select mount and open, after a while it says “you are not authorized to mount this device” …

I the log is shows nothing.

And the funny thing: I have this problem with two extraible drives, both mechanical, both toshiba, both different models. Both of them report the “error probing device” both where working fine beforu upgrading, I can mount both as root without error, i can mount both from command line

:~> udisksctl mount -b /dev/sdc1
Mounted /dev/sdc1 at /run/media/fernando/1c6ac58e-f4ad-4d45-b41a-aacbe8d18390

with log


Oct 09 14:18:11 andromeda kernel: EXT4-fs (sdc1): mounted filesystem 1c6ac58e-f4ad-4d45-b41a-aacbe8d18390 r/w with ordered data mode. Quota mode: none.
Oct 09 14:18:11 andromeda udisksd[2646]: Mounted /dev/sdc1 at /run/media/fernando/1c6ac58e-f4ad-4d45-b41a-aacbe8d18390 on behalf of uid 1001

I have tried them with different cables and different usb ports

deano_ferrari · October 9, 2026, 7:55pm

I’m not seeing anything that clearly explains the authorization failure unfortunately.

I’d try mounting from Plasma using a newly created user to see whether the problem is user-specific or system-wide.

deano_ferrari · October 9, 2026, 8:12pm

It might also be useful to monitor D-Bus in a terminal to see what is happening under the hood…

dbus-monitor "type='method_call',interface='org.freedesktop.UDisks2.Filesystem'"

…and then try mounting the removable device filesystem with the Plasma widget. Anything interesting reported?