I am on fairly recent, mostly clean installation of 42.1. When I want to mount a USB stick from Plasma 5’s Device Notifier, I am asked for the root password. I would expect that a normal should be able to do that.
Here some details:
# dmesg
...
35.428524] sd 3:0:0:0: Attached scsi generic sg2 type 0
36.280974] sd 3:0:0:0: [sdc] 3727360 512-byte logical blocks: (1.90 GB/1.77 GiB)
36.281238] sd 3:0:0:0: [sdc] Write Protect is off
36.281243] sd 3:0:0:0: [sdc] Mode Sense: 23 00 00 00
36.281415] sd 3:0:0:0: [sdc] No Caching mode page found
36.281420] sd 3:0:0:0: [sdc] Assuming drive cache: write through
36.307686] sdc: sdc1
36.309261] sd 3:0:0:0: [sdc] Attached SCSI removable disk
# fdisk -l
...
Disk /dev/sdc: 1.8 GiB, 1908408320 bytes, 3727360 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000
Device Boot Start End Sectors Size Id Type
/dev/sdc1 * 32 3727359 3727328 1.8G b W95 FAT32
# lsusb | lsblk -f
...
sdc
└─sdc1 vfat SCHTICK D0E5-F03D
# ll /dev/sdc*
brw-rw---- 1 root disk 8, 32 Nov 5 19:55 /dev/sdc
brw-rw---- 1 root disk 8, 33 Nov 5 19:55 /dev/sdc1
$ groups
users disk audio floppy video games
The last command shows the groups of the normal user I have the problems with. As you can see, the user is in the disk group.
Just a guess: Does the system (whatever is involved) think the stick is an internal device? The icon in KDE’s Device Notifier looks like a hard disk, not a USB stick.
Any idea?