>> 2-1: USB disconnect, device number 2 >Again, did you plug the cable or did the device spontaneously disconnect? That was a spontaneous disconnect. > In this case, could you retry with > usb-storage quirks=059f:105f:kf Sure! The results are in general a lot more promising (apart from the first line) - plus I was able to read/write files without problems: Dec 08 15:47:48 charon kernel: usb usb2-port6: config error Dec 08 15:47:49 charon kernel: usb 1-6: new high-speed USB device number 4 using xhci_hcd Dec 08 15:47:49 charon kernel: usb 1-6: New USB device found, idVendor=059f, idProduct=105f, bcdDevice= 0.01 Dec 08 15:47:49 charon kernel: usb 1-6: New USB device strings: Mfr=2, Product=3, SerialNumber=1 Dec 08 15:47:49 charon kernel: usb 1-6: Product: 2Big Quadra USB3 Dec 08 15:47:49 charon kernel: usb 1-6: Manufacturer: LaCie Dec 08 15:47:49 charon kernel: usb 1-6: SerialNumber: 00000000250e9e711084 Dec 08 15:47:49 charon mtp-probe[5230]: checking bus 1, device 4: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6" Dec 08 15:47:49 charon mtp-probe[5230]: bus: 1, device: 4 was not an MTP device Dec 08 15:47:49 charon kernel: usb_storage: loading out-of-tree module taints kernel. Dec 08 15:47:49 charon kernel: usb_storage: module verification failed: signature and/or required key missing - tainting kernel Dec 08 15:47:49 charon kernel: usbcore: registered new interface driver usb-storage Dec 08 15:47:49 charon kernel: scsi host5: uas Dec 08 15:47:49 charon kernel: usbcore: registered new interface driver uas Dec 08 15:47:49 charon kernel: scsi 5:0:0:0: Direct-Access LaCie 2Big Quadra v3 051E PQ: 0 ANSI: 6 Dec 08 15:47:49 charon mtp-probe[5239]: checking bus 1, device 4: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6" Dec 08 15:47:49 charon mtp-probe[5239]: bus: 1, device: 4 was not an MTP device Dec 08 15:47:49 charon kernel: sd 5:0:0:0: Attached scsi generic sg3 type 0 Dec 08 15:47:49 charon kernel: sd 5:0:0:0: [sdc] 7814025564 512-byte logical blocks: (4.00 TB/3.64 TiB) Dec 08 15:47:49 charon kernel: sd 5:0:0:0: [sdc] Write Protect is off Dec 08 15:47:49 charon kernel: sd 5:0:0:0: [sdc] Mode Sense: 43 00 00 00 Dec 08 15:47:49 charon kernel: sd 5:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Dec 08 15:47:49 charon kernel: sd 5:0:0:0: [sdc] Optimal transfer size 33553920 bytes Dec 08 15:47:49 charon kernel: sdc: sdc1 sdc2 Dec 08 15:47:49 charon kernel: sd 5:0:0:0: [sdc] Attached SCSI disk Dec 08 15:47:55 charon polkitd(authority=local)[760]: Operator of unix-session:7 successfully authenticated as unix-user:amonra to gain ONE-SHOT authorization for action org.freedesktop.udisks2.filesystem-mount-other-seat for system-bus-name::1.135 [/usr/libexec/gvfs-udisks2-volume-monitor] (owned by unix-user:amonra) Dec 08 15:47:55 charon kernel: exfat: module is from the staging directory, the quality is unknown, you have been warned. Dec 08 15:47:55 charon kernel: exFAT: Version 1.3.0 Dec 08 15:47:55 charon kernel: [EXFAT] trying to mount... Dec 08 15:47:55 charon kernel: [EXFAT] mounted successfully Dec 08 15:47:55 charon systemd[1]: Created slice system-clean\x2dmount\x2dpoint.slice. Dec 08 15:47:55 charon systemd[1]: Finished Clean the /media/amonra/4TB mount point.