NotSoOG wrote I've been trying to load default.xexs but it always fatal crashes on every cod I have.

Do mod menus do this?

I tried updating the xex by patching it with xex tool.
I've uploaded all title updates correctly, I can actually play online but I want to load the solo modes to do other mods.

Does anyone know a fix?

The server mods might be acting up with the mod menus you have put on the console thats my thought but i could be wrong man just re-rip the game using xex menu and restart with a freash rip of the game is what i would tell you and make sure the server mods are disabled

Like @XEXOKLAHOMA previously stated with server issues. Yes, do try changing and checking the server (.ini) configurations and disable the engines within them. Make sure your game mod menus .dll's, and all required xex's/files(.gsc's) are in and not the original ones from game installation. Try re-watching an install video or maybe your game is just plain corrupted. Do you get a fatal crash error, immediate power off to the console, or is it hitting back to the dashboard? And are you running the game from a USB or HDD root or did you transfer files through neighborhood?

Just some questions from me to find solutions.....

I'd love to go over this with you and help you get to where you can successfully launch your desired game alongside modifications.

Best of luck in the meantime!

If you can get online on the games that means you must be able to use the default_mp.xex, if so does it still crash if you just go to the main menu from within the default_mp.xex? You don't have to launch from default.xex you can navigate to single player from the default_mp.xex.