INF File

An INF file is a plain-text script, usually ending in .inf, that Windows Setup reads to know which driver files to copy, which registry keys to write, and which hardware IDs the package supports. When you expand a driver archive and use Device Manager's Update driver wizard, Windows is parsing that INF behind the scenes. If an INF references a file that is missing from the package, installation can fail with a file-not-found error. Opening the INF in Notepad and checking its file lists can confirm whether a required .sys or .dll is present, but Windows should still perform the installation so it can verify signatures and place every file correctly.