Various examples relate to a concept for determining and handling a mismatch between an expected and a current system configuration. An apparatus for a computer system comprises interface circuitry, machine-readable instructions and processing circuitry to execute the machine-readable instructions to obtain information on an expected system configuration of the computer system from a protected storage of the computer system, determine information on a current system configuration of the computer system, compare the expected system configuration with the current system configuration, and provide information on a mismatch via an output device of the computer system if there is a mismatch between the expected system configuration and the current system configuration.