Filter Driver
Definition
A driver that observes or modifies requests in another device stack.
Detailed explanation
A Filter Driver attaches above or below another driver to observe or modify requests. Antivirus, encryption, VPN, accessibility, storage, and peripheral software can use filters without replacing the main function driver. Because filters participate in a shared stack, their behavior can affect otherwise unrelated devices in the same class. Upper filters receive requests before the function driver and lower filters sit closer to the bus, with ordering recorded by device or setup class. File-system minifilters use a specialized framework and altitude order. Removing one layer can change security, encryption, or protocol behavior for the whole stack.
Where you are likely to see it
This term usually appears in Device Manager, Windows recovery tools, Event Viewer, or the installation details for a device package. The definition above gives the short meaning; the detailed explanation describes the term's role in the operating system and hardware stack.
Device status, hardware IDs, and event text identify which Windows subsystem produced a label. This glossary is informational and does not provide repair, installation, or technical-support services.
Related vocabulary
Explore connected concepts and nearby entries in the Windows hardware vocabulary.
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