What process involves checking files during user access and denying access to malicious files?

Real-time scanning is a protective measure employed by security software that continuously monitors files and activities on a system. This process involves scanning files at the moment they are accessed by users, allowing the software to identify and block any malicious files before they can cause harm. By performing these checks in real time, the system ensures that threats are dealt with immediately, preventing them from executing and potentially compromising the system's integrity.

In contrast to real-time scanning, remediation refers to the steps taken to fix or clean up the system after a threat has already been detected. Live protection is a feature that provides ongoing surveillance and defense against threats but can sometimes suggest different operational modes. Device isolation is a method used to restrict or quarantine devices that may be under threat, rather than specifically checking files during user access. Therefore, real-time scanning is the most accurate choice for the process described.