Error mounting /dev/sdb2 at /media/panda/Ubuntu 16.04 LTS amd641: Command-line `mount -t "iso9660" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,iocharset=utf8,mode=0400,dmode=0500" "/dev/sdb2" "/media/panda/Ubuntu 16.04 LTS amd641"' exited with non-zero exit status 32: mount: /dev/sdb2 is write-protected, mounting read-only
mount: wrong fs type, bad option, bad superblock on /dev/sdb2,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.