Dynamic Link Library (DLL) files contain shared instructions that multiple programs use to execute specific tasks. In Crysis 3, the AEyrC.dll file (often interconnected with or mislabeled as CryEA.dll ) handles activation verification and startup protocols. The error usually stems from one of three main culprits:

To play the game without keeping your antivirus off permanently, you must add an exclusion.

Many antivirus programs treat aeyrc.dll as a false positive threat, automatically deleting or quarantining it.