It's essential to use software in compliance with its licensing agreement. Using or distributing software cracks, keygens, or any form of license bypass (including altering Amtlib.dll or similar files) is against the law and can lead to severe penalties.
A: Sometimes false positives happen. Add the After Effects Support Files folder to your antivirus exclusion list, then run the Repair function via Creative Cloud to restore the file. After Effects Cc 2015 Amtlib.dll