Windows 10 IoT Enterprise for Dell Wyse Thin Clients Administrator’s Guide

Unified Write Filter (UWF) is a sector-based write filter that protects your storage media. UWF redirects the write attempts to a virtual overlay, and intercepts the write attempts to the protected volume. This improves the stability, reliability of the device thereby reducing the wear on write media, such as solid-state drives. In UWF, overlay is a virtual storage space that saves changes made on the protected volume. If the file system attempts to modify a protected sector, UWF will copy the sector from the protected volume to the overlay, and the overlay is updated. If an application tries to read from that sector, UWF returns the data from the overlay, so that the system appears to have written to the volume, while the volume remains unchanged.For more information, see the Unified Write Filter documentation at www.microsoft.com.

CAUTION: Failure to keep the Write Filter turned on (except for regular maintenance or Application/Driver installs or upgrades) will prematurely wear out your Flash/SSD storage and invalidate your warranty.

The following are the default registries excluded from being filtered by UWF:

• HKLM\SYSTEM\CurrentControlSet\Control\WNT\DWCADTool
• HKLM\Software\Wyse\ConfigMgmt
• HKLM\SOFTWARE\Microsoft\Windows Defender
• HKLM\SYSTEM\CurrentControlSet\Control\WNT\UWFSvc
• HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\HomeGroup
• HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkList
• HKLM\SYSTEM\WPA

CAUTION: Please follow proper write filter and Windows Page File usage instructions at all times. Such instructions include making sure that the write filter is enabled during regular use and is disabled only temporarily by an administrator when required for image upgrades, applying security patches, registry changes and application installation. The write filter should be re-enabled as soon as such tasks are completed. Such instructions further include never enabling the Windows Page File feature during regular use of the thin client. Any operation of a Dell Wyse Windows Embedded Thin Client with the write filter turned off during regular use and/or with the Windows Page file enabled will prematurely wear out your Flash/SSD storage, decrease performance and decrease the lifespan of the product. Dell is not responsible for, and will not, warrant, support, repair or replace any thin client device or component that fails to operate properly due to a failure to follow these instructions.