Read the below section on mod loading
Known Issues
These are issues we are aware of and are looking to resolve in upcoming updates but will be present in the initial release. Please don't report these as issues as we are well aware of them, thanks.
[SP SOLO]
Solo campaign missions currently behave like coop sessions. So deaths etc are not correctly functioning as expected.
Restart level button in esc menu in both solo zombies & solo campaign don't function correctly and bring you back to the main menu
Dying in solo zombies doesn't restart the map, instead you are put back to the main menu
[SP MODS]
Loading mods from C:\Users\user\AppData\Local\Activision\CoDWaW\mods (Steams location for mods) currently results in issues, e.g. menu not rendering correctly. In the meantime please copy and load your mods from C:\Users\user\AppData\Local\Plutonium\storage\t4\mods instead and they will work as intended.
Some custom zombie maps may not function as expected on the new dedicated servers as these maps were never coded with the ability for players to join mid game in mind, which you can now do on Plutonium. In addition SOLO custom zombies may also have some issues as outlined above in regard to it treating it as an online game so this may also have a knock-on effect. So some issues may occur dependant on the given map.
[MP]
Raw GSC (main_shared) does not work with round-based game modes and will crash the server, run a mod for now if you plan to do gsc w/round-based game modes.
[GENERAL]
T4 is an old game, older games tend to have issues with tabbing in and out. T4 is no exception so currently doing so may result in odd behaviour / crashes.