DefaultInstall

DefaultInstall is a directive used in Windows INF (setup information) files to designate the default installation section that should be processed when an INF is applied by the Windows Setup or driver installation process. INF files are the primary mechanism Windows uses to install drivers and other components, particularly in unattended or OEM deployment scenarios. The DefaultInstall section tells the installer which actions to perform by default, such as copying files, modifying the registry, or registering services.

In practice, a typical INF contains a [DefaultInstall] section that references one or more directives like CopyFiles, AddReg, DelFiles, and AddService. These directives point to other sections within the same INF that contain the actual instructions and file lists. For example, a DefaultInstall block might specify CopyFiles=DriverFiles and AddReg=DriverReg, with separate [DriverFiles] and [DriverReg] sections detailing the specific files to copy and registry changes to apply.

DefaultInstall is especially important for driver packages and other components deployed through SetupAPI, where silent or automated installation is desirable. It is distinct from Windows Installer (MSI) workflows and is central to the behavior of .inf-based installations used by devices and OEM deployments.

Usage considerations include ensuring that the referenced sections exist and are valid, that file and registry paths are correct, and that the installation complies with system security policies. Misconfigurations in DefaultInstall can lead to failed installations or incomplete setups.

See also INF (setup information), SetupAPI, and driver installation.