Problems mounting exfat

zuntik · 2025-10-06 21:35:33

Hi,

I have a strange problem mounting exfat partition from an external disk. I am trying to mount via kde plasma ui. It spends a few secconds checking and then nothing happens. But then, 30 minutes later, the disk suddenly seems mounted. But the behaviour seems very inconsistant.

Has anyone had this problem?

I am using exfatprogs version : 1.2.9
The disk label type is gpt
the partition is exfat and the partition type is "Microsoft basic data".

Scimmia · 2025-10-06 22:46:22

What happens when you mount it from a command line?

zuntik · 2025-10-07 17:17:40

I would mount it with "sudo mount -t exfat /dev/sdb1 /mnt/b1". That would work straight away but the files would be read only by my personal user.

seth · 2025-10-07 20:02:58

https://man.archlinux.org/man/mount.8.e … ns_for_fat - you'll have to change the umask/dmask
How exactly do you mount the FS w/ KDE? Are you being asked for a password at any moment?

zuntik · 2025-10-07 23:02:41

Mounting via the desktop environment usually is as simple as clicking "Mount and Open" when a popup appears as soon as I plug in the hard disk. When I do press the button, it appears as "Checking..." and then nothing happens. The button goes back to "Mount and Open".
The command:

sudo mount -t exfat -o umask=000,uid=1000,gid=1000 /dev/sda1 /mnt/a1

worked as expected: works straight away and I can write to the mount point.
Supposedly, the following command:

udisksctl mount -b /dev/sda1

should work like when I press the "Mount and Open" button but when I do, the command just stalls. It doesn't complete.

seth · 2025-10-08 07:51:03

Can you udisksctl mount other devices?

grep -r exfat /etc/udisks2

zuntik · 2025-10-09 18:38:44

Here is the result:

➜ grep -r exfat /etc/udisks2 
/etc/udisks2/mount_options.conf.example:# # common options for both the native kernel driver and exfat-fuse
/etc/udisks2/mount_options.conf.example:# exfat_defaults=uid=$UID,gid=$GID,iocharset=utf8,errors=remount-ro
/etc/udisks2/mount_options.conf.example:# exfat_allow=uid=$UID,gid=$GID,dmask,errors,fmask,iocharset,namecase,umask

zuntik · 2025-10-09 18:46:21

right now I just ran

➜ udisksctl mount -b /dev/sda2
Mounted /dev/sda2 at /run/media/<user>/<label>

and it mounted the device quickly.
But then I unmounted and repluged and the mount is back to not working again. It is very inconsistent behaviour. It seems like mounting only works after the disk has been pluged in for a while.

I tested mounting an external ssd with exfat and it continues to never have any problem.

I would say that the problem is with the disk but I have have any trouble mounting it to windows.

seth · 2025-10-09 19:39:58

I would say that the problem is with the disk

tail the system journal or dmesg,

sudo journalctl -f

plug the disk and try to mount it - post the messages that generates.

zuntik · 2025-10-10 18:22:25

I started "sudo journalctl -f" and then plugged in the disk:

sudo journalctl -f
Oct 10 19:17:05 hostname kernel: Buffer I/O error on dev sdb2, logical block 85793248, async page read
Oct 10 19:17:05 hostname kernel: Buffer I/O error on dev sdb1, logical block 115820160, async page read
Oct 10 19:17:05 hostname kernel: Buffer I/O error on dev sdb1, logical block 115820192, async page read
Oct 10 19:17:05 hostname kernel: Buffer I/O error on dev sdb2, logical block 85971744, async page read
Oct 10 19:17:05 hostname kernel: sd 1:0:0:0: [sdb] Synchronizing SCSI cache
Oct 10 19:17:05 hostname kernel: sd 1:0:0:0: [sdb] Synchronize Cache(10) failed: Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK
Oct 10 19:17:05 hostname kded6[1236]: Failed to notify "Created too many similar notifications in quick succession"
Oct 10 19:17:08 hostname sudo[6353]: pam_unix(sudo:session): session closed for user root
Oct 10 19:17:09 hostname sudo[7008]:   user : TTY=pts/4 ; PWD=/home/user ; USER=root ; COMMAND=/usr/bin/journalctl -f
Oct 10 19:17:09 hostname sudo[7008]: pam_unix(sudo:session): session opened for user root(uid=0) by user(uid=1000)
Oct 10 19:17:12 hostname kernel: usb 2-2: new SuperSpeed USB device number 5 using xhci_hcd
Oct 10 19:17:12 hostname kernel: usb 2-2: New USB device found, idVendor=0bc2, idProduct=331a, bcdDevice= 9.15
Oct 10 19:17:12 hostname kernel: usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Oct 10 19:17:12 hostname kernel: usb 2-2: Product: Expansion Desk
Oct 10 19:17:12 hostname kernel: usb 2-2: Manufacturer: Seagate
Oct 10 19:17:12 hostname kernel: usb 2-2: SerialNumber: NAAAGAH2
Oct 10 19:17:12 hostname kernel: scsi host1: uas
Oct 10 19:17:12 hostname kernel: scsi 1:0:0:0: Direct-Access     Seagate  Expansion Desk   0915 PQ: 0 ANSI: 6
Oct 10 19:17:12 hostname kernel: sd 1:0:0:0: [sdb] Spinning up disk...
Oct 10 19:17:12 hostname mtp-probe[7016]: checking bus 2, device 5: "/sys/devices/pci0000:00/0000:00:14.0/usb2/2-2"
Oct 10 19:17:12 hostname mtp-probe[7016]: bus: 2, device: 5 was not an MTP device
Oct 10 19:17:12 hostname mtp-probe[7017]: checking bus 2, device 5: "/sys/devices/pci0000:00/0000:00:14.0/usb2/2-2"
Oct 10 19:17:12 hostname mtp-probe[7017]: bus: 2, device: 5 was not an MTP device
Oct 10 19:17:12 hostname kded6[1236]: Failed to notify "Created too many similar notifications in quick succession"
Oct 10 19:17:19 hostname kernel: .......ready
Oct 10 19:17:19 hostname kernel: sd 1:0:0:0: [sdb] 7814037167 512-byte logical blocks: (4.00 TB/3.64 TiB)
Oct 10 19:17:19 hostname kernel: sd 1:0:0:0: [sdb] 4096-byte physical blocks
Oct 10 19:17:19 hostname kernel: sd 1:0:0:0: [sdb] Write Protect is off
Oct 10 19:17:19 hostname kernel: sd 1:0:0:0: [sdb] Mode Sense: 53 00 00 08
Oct 10 19:17:19 hostname kernel: sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Oct 10 19:17:19 hostname kernel: sd 1:0:0:0: [sdb] Preferred minimum I/O size 4096 bytes
Oct 10 19:17:19 hostname kernel: sd 1:0:0:0: [sdb] Optimal transfer size 33553920 bytes not a multiple of preferred minimum block size (4096 bytes)
Oct 10 19:17:19 hostname kernel:  sdb: sdb1 sdb2
Oct 10 19:17:19 hostname kernel: sd 1:0:0:0: [sdb] Attached SCSI disk
Oct 10 19:17:19 hostname systemd[1]: Started dbus-:1.1-org.kde.kded.smart@3.service.
Oct 10 19:17:29 hostname systemd[1]: dbus-:1.1-org.kde.kded.smart@3.service: Deactivated successfully.

The last message before plugin in was "Started dbus-:1.1-org.kde.kded.smart@3.service."
Then, after pluggin in, I tried to mount as described before but nothing happened. The mount did not happen and no new messaged appeared.

zuntik · 2025-10-10 19:16:06

I plugged it again with the same procedure and waited for it to finally mount:

Oct 10 20:00:51 hostname systemd[1]: Started dbus-:1.1-org.kde.kded.smart@5.service.
Oct 10 20:01:00 hostname systemd[1014]: Started Dolphin - File Manager.
Oct 10 20:01:01 hostname systemd[1]: dbus-:1.1-org.kde.kded.smart@5.service: Deactivated successfully.
Oct 10 20:07:56 hostname kernel: exFAT-fs (sdb2): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
Oct 10 20:08:03 hostname udisksd[1092]: Mounted /dev/sdb2 at /run/media/user/label on behalf of uid 1000

Last edited by zuntik (2025-10-10 19:32:42)

seth · 2025-10-10 19:27:55

The last message before plugin in was "Started dbus-:1.1-org.kde.kded.smart@3.service."

There're some IO errors and KDE seems to trigger and hang in a smartctl check…

sudo smartctl -a /dev/sdb

Make sure that sdb is the relevant disk and post the entire output.

zuntik · 2025-10-10 23:07:13

Here it is:

-> sudo smartctl -a /dev/sdb

smartctl 7.5 2025-04-30 r5714 [x86_64-linux-6.17.1-arch1-1] (local build)
Copyright (C) 2002-25, Bruce Allen, Christian Franke, www.smartmontools.org

Read Device Identity failed: scsi error unsupported field in scsi command

If this is a USB connected device, look at the various --device=TYPE variants
A mandatory SMART command failed: exiting. To continue, add one or more '-T permissive' options.

seth · Yesterday 07:24:15

Is the drive attached and available at this point?
What is model that disk specifically?

For the time being, you should rather not trust it.

Arch Linux

#1 2025-10-06 21:35:33

Problems mounting exfat

#2 2025-10-06 22:46:22

Re: Problems mounting exfat

#3 2025-10-07 17:17:40

Re: Problems mounting exfat

#4 2025-10-07 20:02:58

Re: Problems mounting exfat

#5 2025-10-07 23:02:41

Re: Problems mounting exfat

#6 2025-10-08 07:51:03

Re: Problems mounting exfat

#7 2025-10-09 18:38:44

Re: Problems mounting exfat

#8 2025-10-09 18:46:21

Re: Problems mounting exfat

#9 2025-10-09 19:39:58

Re: Problems mounting exfat

#10 2025-10-10 18:22:25

Re: Problems mounting exfat

#11 2025-10-10 19:16:06

Re: Problems mounting exfat

#12 2025-10-10 19:27:55

Re: Problems mounting exfat

#13 2025-10-10 23:07:13

Re: Problems mounting exfat

#14 Yesterday 07:24:15

Re: Problems mounting exfat

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