I’ve followed every guide out there; I have the chd file in a folder named after the zip, both inside the zip folder and they simply won’t load. Every other mame game works fine…
Edit: So chd games run perfectly fine in mame standalone but not retroarch?
CHDs work in RetroArch.
Do you use the same files as the standalone, with the same folder structure (chd inside it’s folder and the rom outside, both the folder and rom having the same name?)
Do you also use the same MAME version? If either the chd or rom aren’t the same romset version as MAME’s version, there’s a chance of incompatibility. The bigger the gap between the romset and MAME versions, the bigger the chance of the games not working.
Same files, same folder structure, same mame version…
What other files are in the roms folder? I assume in your standalone MAME roms folder you also have all the bios files. Make sure RetroArch can also see those files. Basically, a game may need 3 files to run, the rom, the CHD and the bios.
It could also be a path issue. Standalone MAME has it’s own UI where you double click the game in the list and it works. How are you trying to load those CHDs in RetroArch?
Up to 4 files if it’s a clone romset. While i don’t know of any, there might also be romsets that require several bioses (1 for the main board, 1 for the sound board, …).
@brothanigus logs would probably help
Are you saying that you have the zip inside the same folder as the chd? If so that is incorrect. The chd needs to be in a folder with the zip name but the zip needs to be outside the folder.
I am assuming you are trying to run an arcade chd?
What chd are you trying to run. I will see if I can get it to work.
It would be faster if you could post a log. 
The roms boot in the standalone mame emulator with the exact same folder structure. Retroarch simply will not load CHDs.
How do I get a log?
Edit: Things work fine now. Updated retroach.