“Stuck on Awaiting challenge… in T6 Zombies right after changing language usually points to broken/mismatched localization files or cached profile data. Plutonium only supports English game files; manual language swaps are unsupported and can break ZM loading even if MP still works.

Try this (in order):

Restore stock English files via Steam: set BO2 to English in Steam → Properties → Language, then Verify integrity to pull the original localization/zone files back. Remove any custom localization.txt you dropped in. (Plutonium only provides/supports English.)

Repair your BO2 folder path in the Plutonium launcher (Game Settings → reselect the BO2 folder) to ensure it points at the clean Steam install.

Reset cached configs/stats:

Delete or regenerate …\AppData\Local\Plutonium\storage\t6\gamesettings (some users fixed ZM loading by refreshing this).

If you still hang, your stats cache may be corrupted—run resetStats or delete …\AppData\Local\Plutonium\storage\demonware\18397 (this wipes progress).

Whitelist Pluto in your antivirus (false positives can block files) and kill overlays/injectors (Discord/Steam overlay, RTSS/Afterburner, etc.).

DLC check: if you’re trying to join a ZM server running a DLC map, make sure those DLC files exist in your install—otherwise you’ll fail to load/handshake.

If none of that helps, share your BO2 path, exact map/server, and what you changed in localization so folks can spot a mismatch quickly.