"Serial number is invalid"

[Box Ocelot]

Just picked up RA3 from the sale and when attempting to play with a friend it gives me this error. Anyone else having this problem

[Tediak]

I am having this same issue and put in a support ticket. I suggest doing the same. You can verify that your CD Key is the same in your registry as provided by Steam by doing the following steps:


Open your Registry Editor - You can do this simply by pressing the start button, type "regedit" and press enter
Navigate through NKEY_LOCAL_MACHINE / SOFTWARE / Wow6432Node / Electronic Arts / Electronic Arts
There should be a Red Alert 3 folder in there with a subfolder called ergc - Go into that folder - Attention, there also is a red alert 3 folder under just once Electronic Arts instead of Electronic Arts / Electronic Arts. This folder will not have a subfolder!
The ergc folder should contain a (Default) value of the type REG_SZ with the DATA of your serial key without any - between the blocks
If that's not the case, right click, new / string value, enter as name (Default) and as data your serial code without any - or space.