There is a way I figured out how to temporary fix it. First, in the login screen click on the modify serial code for the multi-player (be sure to input ur serial code before attempt any login. Then try to input ur serial code with different combination of caps for ur serial code. For example, 4r8K-9R7u just mixed up the capital letter combination should work for a bit.

I'm sure that with the overwhelming number of people that can't play multiplayer despite trying all the tricks that EA will be working on it asap. Hopefully they don't pull a treyarch/activision on this title.

I had success with putting my serial in with dashes but using lower case letters. Before I got into the game, I exited so it would "save" the serial in the system. I opened the game and was able to join a server.

Hrmm me and my buddy were having the same issue and this fix both worked for us. Before you log in click the modify cd key button and enter your cd key in all lower case with no dashes. After that connect to a NON official crytek server (usually the USplay ones) once you connect in the lobby exit your game back to desktop. Re launch crysis 2 click the modify button before login re-enter cd key lower case with no dashes launch multi and attempt to connect to official servers. May not work for all but this worked for my buddy and I soooo best of luck

I actually tried this method.. no dashes and join empty server worked. So i went to Single Player and quit. Then i went to my USER saved game files and set my PROFILE to not read only. Then launched the game as adminstrator. Input cap keys and dash at modify first then login. Then i could join some ranked server but we already know the server won't start eventhough it was full. So i joined another one and BAM i'm in! It was fun but sadly got disconnected from the host. Gamespy server probably have problems same as the game. I am sure Crytek is working hard to accomplish and fix all these issues. Give them time. Seriously keep trying to do the code thing and eventually you will be able to get online and play but watch out for the disconnection crap.

I even opened the console to see what it said and i did spotted "Gamespy Server Unavaliable" Could be server side issue. I hope this "Serial Code in use." gets fixed asap. They will fix it. Best chance is to wait and give developers time to tackle the issue and just go play single player. Hope this helps.

I actually tried this method.. no dashes and join empty server worked. So i went to Single Player and quit. Then i went to my USER saved game files and set my PROFILE to not read only. Then launched the game as adminstrator. Input cap keys and dash at modify first then login. Then i could join some ranked server but we already know the server won't start eventhough it was full. So i joined another one and BAM i'm in! It was fun but sadly got disconnected from the host. Gamespy server probably have problems same as the game. I am sure Crytek is working hard (Haha, Yeah, Right.....) to accomplish and fix all these issues. Give them time. Seriously keep trying to do the code thing and eventually you will be able to get online and play but watch out for the disconnection crap.

I even opened the console to see what it said and i did spotted "Gamespy Server Unavaliable" Could be server side issue. I hope this "Serial Code in use." gets fixed asap. They will fix it. Best chance is to wait and give developers time to tackle the issue and just go play single player. Hope this helps.

Why are you copying my post and revising it? Grow up?

Crytek is WORKING hard on this. I got a confirmation from one of the crytek employees. Maybe shut the **** up and don't be a baby?

Why are you copying my post and revising it? Grow up?

Crytek is WORKING hard on this. I got a confirmation from one of the crytek employees. Maybe shut the **** up and don't be a baby?
While you're being a little too harsh, I agree. JUST BECAUSE THERE ISN'T A FIX NOW, DOESN'T MEAN THEY AREN'T WORKING ON IT. They can do only so much at a time, patches can only be so big, and games always have a few bugs when they come out.(If you've ever played an MMO on day 1 you know what I'm talking about)
Edit: And no, this is not one of the worse launches. If you want to hear about a bad launch ask someone who played during WoW's launch.

i posted it before, but... you know what helped me? i changed 1 letter in my key, so it was wrong one, but it worked! wtf?

I ain't doing that. Seems stupid.

Same thing is happening to me I am trying to play a game and I get SERIAL IN USE error. What gives?!@!?

Having the same issue.

ME2 <3

Having the same issues. I'm sure EA is working on it, although it is very disappointing.

Yup, i just installed it and my apparent code is in use too

i had the issue, but fix'd it.

I entered the Serial Code with CAPs and dashed in the menue where i have tio login with my login details.
than i entered multiplayer mode, and than left to singelplayer, entered multiplayer mode and than turned the game off. After this i had no more this error.

This is what happened to me in COD 4. Crysis 2 arriving tomoz so hopefully won't have same problem