Device Installations Requiring a Reboot

Device installations should not force the user to reboot the system unless absolutely necessary. The following circumstances are the only ones for which a system reboot should be necessary:

• Installing or removing a non-Plug and Play device.

  For these legacy devices, a user typically must shut down the system before physically adding or removing the device. After the power is turned back on, the system reboots. Note that the device's setup files should not initiate a reboot, regardless of whether the user installs the drivers before or after plugging in the hardware.

• Updating a driver for a system boot device.

  If a device can potentially hold the system's paging, hibernation, or crash dump file, its drivers must service IRP_MN_DEVICE_USAGE_NOTIFICATION requests. The system sends this request before placing one of these files on the disk. If the drivers succeed the request, they must fail any subsequent IRP_MN_QUERY_REMOVE_DEVICE requests. When a driver for the device fails an IRP_MN_QUERY_REMOVE_DEVICE request, the system prompts the user to reboot. Note that the device's setup files should not initiate a reboot.

• Installing a non-WDM filter driver.

  If a filter driver is added to a non-WDM driver stack, the system must be rebooted. In this case, the driver's installer or co-installer should request a reboot (see Initiating System Reboots During Device Installations). Note that adding a filter driver to a WDM driver stack does not require a reboot, unless an underlying device is a system boot device.

Avoiding System Reboots During Device Installations

To avoid system reboots during device installations, use the following rules:

• Never use Reboot or Restart entries in INF DDInstall sections, except for installations specific to Windows 9x/Me.
• Do not use COPYFLG_FORCE_FILE_IN_USE, or COPYFLG_REPLACE_BOOT_FILE flags with INF CopyFiles directives, unless absolutely necessary.
• Assign a new file name to each new version of a class installer or co-installer, or a service DLL. This avoids the necessity of a reboot if an older version is in use. (In fact, if a new file name is not used for an updated class installer or class co-installer, these new files will not be used for the installation.)
• To update a device's drivers, follow the rules listed under Updating Driver Files.

Initiating System Reboots During Device Installations

In the rare cases in which it is necessary for the system to be rebooted to complete a device installation, use the following rules:

• During initial installations, a device's installer or co-installer can request a system reboot by setting DI_NEEDREBOOT in the SP_DEVINSTALL_PARAMS structure, which is received along with device installation function codes. (This should not be done unless absolutely necessary.)
• During update installations, a device's installation application can call UpdateDriverForPlugandPlayDevices, which determines whether a reboot is necessary.