no mountable file systems issue with ISO
I have High sierra installed and have downloaded many copies of linux distro .ISO's but cannot open or install them. I get "no mountable file systems" no action at all from Drive Utility or "the disk you inserted was not readable by this computer" when I did "hdiuti burn linuxmint-19-mate-64bit-v2.iso" in terminal. I also burned iso's on Windows machines but get the same result.
iMac (21.5-inch, Late 2013), OS X El Capitan (10.11.2)