I will wait for the next patch this suck, i hate do this for still my stats and unlocks

Something happening again !!!! Had this issue a few days ago but typing the key in mp, going to single, ending game exe and repeting 3 times solved it for me. But now im comming from a walk with the dog and I had my MP open and when entering a serwer it said "incorect key" and when I logged of and logged in the SP logged fine but mp didnt work. I tried the same fix like last time but this time it dosnt work :( this **** is infuriating

Tried this several times and still didn't work :/ I've only been able to access the multiplayer once and since then cant play.

tried login in today and it worked !!!!!! OMG do the cd-key severs got a bad day or is it just pure bad luck it dosnt work.

Nvm after playing some now it dosnt work again -.-` Just gonna quit this game too much hastle.

Didn't check if this has already been mentioned:

Trying to preform the steps as described in the opening post, things turned out okay, but different then expected.

Step one requires me to enter my key, as I enter multiplayer-mode, so I skipped entering my key at startup. (The fact that you can enter your code at startup, before given the chance to select multiplayer, wasn't taken into acount by the O.P.)

After preforming steps one and two, the game didn't even allow me to preform step three. The key-code was already locked in there. And indeed, after rebooting the game, step three turned out to be unnesecery.

So:
1: When first given the chance to enter your key at startup, select "skip"
2. Enter multiplayer (which gives you the same screen you get at startup) and enter your key.
3. Et voila.

The problem appears to be, that the game stores your key online, and will only do so while in multplayer mode. If you enter the code at startup, and go to multiplayer next, the code-entering takes place too early to trigger the storage. But that's just my layman's analysis.

Thanks Im gonna try that have the same problemo lol!

trying to join a server in the multiplayer. conects then says " serial code is incorrect. a valid serial code is requried to play multiplayer" go back to my login screen enters my profile then wont join same txt appears when trying to join.

I have a problem when I enter cd key crysis 2 I wrote "the limit of activations for that serial number has been exhausted"
Do not reinstall the crisis 2 to 3 times and then you will not play

I can't log In to MP, I try every single combinations to resolve my problem but now I wait 1 week to resolve this problem! How it's possible in so big company and so popular game have so silly bugs!! WTF!

Well... its really annoying, but it just does not work, i tried everything but for some reason the serial key does not change it just keeps saying: "****-****-****-****-0000" and when i try to join a match it says "Serial code is incorrect. A valid serial code is required to play Multiplayer"... i guess the only way im gonna be able to play is through the patch, so i'll have to wait... :/