Did you Play The "AntiCheat Disabled" option?

Having the same problem. And yes, "anticheat disabled" was chosen before launching.

exact same problem anti cheat off mod is installed and NOTHING IT DIFFERENT IM GETTING MAD THAT THIS DOESN'T WORK!

has anybody figured it out?

Anything new?

also having this issue

It downloaded for me bc it turned out I didn't have space for it, idk if that would be your issue tho.

I got it working just fine with these steps: unsubscribe from Cursed Halo Again in the workshop. Launch Halo MCC normally. Install Halo CE Campaign AND Multiplayer. Exit and let those finish. Subscribe to Cursed Halo Again. Launch Halo MCC with EAC deactivated (should be a menu that comes up when launching). Click Campaigns > Halo CE Anniversary > Cursed Halo Again.

Ran into the same issue on Linux. Launching with anti-cheat off, and the mod is definitely installed. Mod just wasn't listed in the Campaign menu.

The problem was the Proton version. I had my compatibility settings set to Proton 6, and it seems mods aren't working for me unless I set the forced compatibility option to Proton 7 or higher. (Normally I run Experimental but this machine has an old GPU, which no longer worked in Proton 8).

引用自 Snek：

I got it working just fine with these steps: unsubscribe from Cursed Halo Again in the workshop. Launch Halo MCC normally. Install Halo CE Campaign AND Multiplayer. Exit and let those finish. Subscribe to Cursed Halo Again. Launch Halo MCC with EAC deactivated (should be a menu that comes up when launching). Click Campaigns > Halo CE Anniversary > Cursed Halo Again.

this worked for me