I started with 4.17 Unreal Engine on my OSX laptop about 1/2 year ago and fixed the case sensitive file name issues (using symbolic links) and was developing fine with it.
Just downloaded 4.18.3 and now it refuses to run with junky message about not working on case-sensitive file systems.
I cannot switch to case-insensitive - I have been using case-sensitive on OSX for 17 years - because I need consistency with Linux file systems.
I have 1TB which is already mostly allocated so cannot re-partition to have case-insensitive partition. Dont want the performance penalty of a case-insensitive dmg mounted.
Why disable this totally?
Could you not have an option to continue if we know what we are doing?
(For the record I have built 4.18.3 from source on another Linux system of mine and it works fine so I really dont understand why you cant get case-sensitive to work on OSX - in fact I was attempting to update OSX to be consistent with UE4 version Im using on Linux).
I am working on building from source on OSX case-sensitive by commenting the junky check code in Engine/Source/Runtime/ApplicationCore/Private/Mac/MacPlatformApplicationMisc.cpp.
Otherwise may have to just binary edit the appropriate places in the downloaded version to skip the check.
Im impressed by how well Unreal Engine works on Linux and really a case-sensitive issue is because hard coded filenames or stored filenames are actually different from the on disk filenames - your Linux build already renames PNG files to png among some other fixes - which seems to be repeated in the Mac Build BatchFiles script FixDependencyFiles.sh.
(Ps yes Im running your launcher on case-sensitive - that also has issues with names plus Library/Application Support/Epic - that I can fix by mounting a small dmg and symbolic linking into ~/Library/Application Support/Epic - but I dont usually as I only loose the Learn section if I dont use the dmg).