Hello Tomzxc.
Please check the BattlEye faq. https://www.battleye.com/support/faq/

When starting my game with BattlEye enabled, I get the following error message: “Windows cannot access the specified device, path, or file. You may not have the appropriate permission to access the item.”

This is likely caused by you trying to use an unsupported Windows 10 Insider build. While we try to support the latest builds as fast as possible, there can sometimes be delays related to a number of factors. Until then you will have to downgrade to an official public build of Windows 10.

Regards,
Geez