A computer includes a filter module providing a standardized interface for intercepting file access requests. The computer also includes a cache manager that manages the caching mode used with the requests. An application on the computer issues a file access request and explicitly or implicitly specifies a cache hint informing the cache manager of a desired caching mode. A security scanner module scans files on the computer for malicious software. The security scanner module intercepts a file access request and alters the caching mode, if necessary, to one optimized for security scanning. The security scanner module performs the file scan using the optimal caching mode, and, if necessary, resets the caching mode to its original state.