I just installed Debian Jessie KDE edition ISO and I got problem to save
the files to USB memory stick.
Then I checked the the permissions of the USB stick and it was root:root.
I finally fixed it by commenting out following line on /etc/fstab-file:
Now it works just great at least in KDE.
The reason for the issue is that if you install Debian from a USB drive, the installer adds sdX1 to fstab and whenever you plug it in the system will mount it as root.
So you should always remember to uncomment that line from fstab after installing from USB.
Then I checked the the permissions of the USB stick and it was root:root.
I finally fixed it by commenting out following line on /etc/fstab-file:
#/dev/sdf1 /media/usb0 auto rw,user,noauto 0 0
Now it works just great at least in KDE.
The reason for the issue is that if you install Debian from a USB drive, the installer adds sdX1 to fstab and whenever you plug it in the system will mount it as root.
So you should always remember to uncomment that line from fstab after installing from USB.