Either you hadn't actually changed the bitcoin.conf file, or it got lost. Bitcoin Core has either found an empty bitcoin.conf or did not find one at all.
For reference: I've successfully reproduced the issue by setting the bitcoin.conf file as "
read-only":
If it's missing, core will make one, once he clicked the "
open config file" button without errors; if the whole folder was set to read-only (
or a permission issue), core fails to launch at all.
So BlackHatCoiner might have set it to read-only for some reason or the file became inaccessible.