No USB flash drive can be mounted on XFCE. Both lsusb and lsblk 
correctly show the device, showing that the device is not 
malfunctioning.

Fdisk can access and modify the partitions on the device but gparted 
will segfault right after it finishes to search for devices. You can 
find my config.scm as an attachment.

This is the output of `guix describe`:

Generation 201	Jul 23 2019 21:53:47	(current)
   guix c42db89
     repository URL: https://git.savannah.gnu.org/git/guix.git
     branch: master
     commit: c42db89ff992037841e7937059db952571af86fa