Taken from BattlEye.com.
When launching the game I get a “Failed to install BattlEye Service” / “BattlEye Service installation failed” / “Failed to start BattlEye Service” / “BattlEye Service startup failed” / “Failed to initialize BattlEye Service: …” error. How can I solve this?
This happens if something on your system prevents the installation/startup of the BE Service, which is required to play on BE-enabled servers.
Please ensure that any security software (anti-virus, etc.) running on your system doesn’t block the BE Service (both BEService.exe/BEService_x64.exe in your game’s “BattlEye” directory as well as the entire BE Service directory, which is usually “C:\Program Files (x86)\Common Files\BattlEye”) in any way. You might have to add it to your security software’s exception list.
If that doesn’t help or you don’t use any sort of security software there might be a permission issue with your BE Service directory or the files within it. To solve this delete the BE Service directory (usually “C:\Program Files (x86)\Common Files\BattlEye”) and then try to launch your game again.
If you still get the same error at this point please try to manually set the BE Launcher in your game directory (usually the executable file with “_BE” at the end) to run with administrative privileges (normally this should happen automatically). To do so right-click on the BE Launcher executable, choose “Properties”, go to the “Compatibility” tab, check the “Run this program as an administrator” option and click OK to apply your changes.
If you still can’t get it to work some unknown software running on your system might be blocking BE somehow or certain parts of your operating system might be broken. If you cannot determine the cause we would suggest a repair re-installation of Windows as a definite solution.