Re: Mass Effect 3 Cannibals won't die

They do not take damage. When I shoot them with my pistol their health bar just flashes but no damage is done at all

That would be what happens if they've scavenged armor plates to cover their body parts from other cannibals and husks and they need to be blasted off before they take damage there. Are you absolutely sure that you're not shooting them somewhere where they're covered as that would be what normally would happen in such a case.

I am 100% certain I am not shooting them in an armoured location. I've tried concussion blasts and all the ammo types and nothing seems to damage them. A concussion blast once brought one of them down to half health but then he wouldn't take damage after that. They also kill me in 5 shots which is pretty strange as I am playing on the normal difficulty, I did try changing difficulty to narrative and that didn't change anything either   

That sounds very, very strange indeed. Almost sounds like some sort of a copy protection even. I've never heard of something like this. On Multiplayer it sometimes happens that an occasional enemy just won't take any damage but on a singleplayer I've never heard of this.

All I can think of is trying to goto Origin and either Repair the installation or uninstalling it and installing again from the scratch and seeing if it still persists. If it does, then something really strange is going on.

I'll try that tomorrow because I have slow internet so downloading it will take a long time

@NoFookinClue

Before you reinstall, try to repair the game. (in Origin > Game Library > right click ME3 > Repair)