PhpStorm < 10

Up to PhpStorm9 it was possible to set case sensitivity by adding:

idea.case.sensitive.fs=true

to idea.properties file, which you can open using “Help -> Edit Custom Properties” in PhpStorm itself.

PhpStorm  >= 10

It Seems that in versions 10 and later you need to use idea.properties file from “Help -> Edit Custom Properties” but also need to add this line to another idea.properties file:

echo 'idea.case.sensitive.fs=true' >> /Applications/PhpStorm.app/Contents/bin/idea.properties

GIT case sensitivity

Remember also that GIT has it own setting for case sensitivity and it may be turned off on your environment, because MacOS does is not case sensitive by default. You can turn it on by:

git config core.ignorecase false