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Installing Updates on an EWF-Protected Run-Time Image

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Because EWF prohibits write access to a volume, there are additional considerations to make when you want to install an application or update your run-time image with a QFE.

To disable the current EWF overlay, use the ewfmgr disable command. After you disable the EWF overlay, you must reboot the system and then install your application.

Note   For EWF RAM Reg mode, you must use the

ewfmgr

commitanddisable

command to disable EWF. The

ewfmgr commitanddisable

command applies all changes in the overlay to the protected volume, even those that are unrelated to your application installation or QFE update. To minimize additional write operations to your volume, you can clear the overlay cache by rebooting the device before you install any applications. For more information, see EWF RAM Reg Mode.

Additionally, you can use the EWF API functions to programmatically control EWF Manager to disable EWF. For more information about using the EWF APIs, see Enhanced Write Filter API.

To apply a QFE or other update, you must use one of the following procedures:

To update a run-time image that is protected by EWF Disk or RAM mode

  1. Use EWF Manager to disable the overlay by using the following command:

    ewfmgr c: -disable

  2. Reboot the system.

  3. Install the application or QFE update.

  4. Re-enable the EWF overlay by using the following command:

    ewfmgr c: -enable

  5. Reboot the system to re-enable the EWF overlay.

To update a run-time image that is protected by EWF RAM Reg mode

  1. Reboot the device to clear the RAM overlay.

  2. Commit the overlay to the protected volume and disable the EWF overlay by using the following command:

    ewfmgr c: -commitanddisable

    Because RAM Reg modes store EWF configuration data in the registry, you must commit the disable change to the protected run-time image. For more information, see EWF RAM Reg Mode.

  3. Reboot the system to disable the overlay.

  4. Install the application or QFE update.

  5. Enable the EWF overlay by using the following command:

    ewfmgr c: -enable

  6. Reboot the system to re-enable the EWF overlay.

See Also

Design Considerations for Using EWF with Device Update Agent | Device Update Agent | Enhanced Write Filter | Troubleshooting Enhanced Write Filter | EWF Design Considerations

Last updated on Wednesday, October 18, 2006

© 2006 Microsoft Corporation. All rights reserved.