A system and method for optimizing a process of synchronization of a database of files checked by an anti-virus (AV) application implemented as a special AV driver. The database is updated by a special interface application using a log file and the AV driver cache. The AV driver monitors modifications of the files and records modification-related information in the context of the modified files. The AV driver creates and maintains a log of modified files. The AV driver supports a circular cache containing minimal required information about the modified files. This information is used for identification of the modified files by an application providing an interface between the AV driver and the database of checked files.