There are several possible fixes for this issue.

This is a video on the dayz mod for arma 2 operation arrowhead, it fixes bad serial number given in setup, or bad cd key etc. Please give it a like and subscribe! Type ON search REGEDIT. I'm getting a fatal error when I start up ARMA OA through SixUpdater, stating that I gave a bad serial code. I've verified the game cache, done a.

First, run Arma 2 once. Then try to run Arma BAF(without beta or DayZ). If that won't help you can try to verify game cache of the Arma 2 and Arma OA.

Arma Gold Bar Serial Number Given In Setup

1.) If that will not help, follow this guide:

1. RUN STEAM AS ADMINISTRATOR
2. Exit Steam.
3. Right-click on Steam icon.
4. Left-click on 'Run As Administrator'.
5. If the problem persists, reboot your computer and try the procedure again.

2.) DELETE ARMA 2 BAF REGISTRY ENTRIES

1. Exit Steam, open Start menu and type this directly into the menu (in Windows XP, you will have to click on 'Run' first) regedit
2. Press Enter.
3. In regedit window, click on HKEY_LOCAL_MACHINE.
4. Press CTRL+F to bring up search.
5. Look for 'ArmA' (without the quotes).
6. Delete all the 'ArmA' entries you find from the registry.
7. Run Steam as Administrator.
8. Right-click on the game in Steam Library.
9. Click on 'Properties'.
10. Select 'Local files' tab and click on 'Verify integrity of game cache files' button.
11. Please wait, the process can take several minutes.

3) REINSTALL STEAM

Serial Number Idm Terbaru

1. Go to Steam's installation folder.
2. Delete everything there except 'steam.exe' and 'steamapps' folder.
3. Run 'steam.exe' - Steam will reinstall itself automatically.