Turn on, enable, or configure UWF on a device (Industry 8.1)
7/8/2014
Learn how to enable, disable and configure Unified Write Filter (UWF) on your Windows Embedded 8.1 Industry (Industry 8.1) device.
You can use Unified Write Filter (UWF) to help protect your physical storage media on your Windows Embedded 8.1 Industry (Industry 8.1) device. UWF is turned off by default, so in order to use UWF you must first turn on UWF and then enable it. You must also configure UWF to protect at least one physical storage device.
For more information about UWF, see Unified Write Filter.
Turn UWF on or off
By default, UWF is not turned on. You can turn UWF on or off for your Industry 8.1 device by using the following steps:
To turn UWF on or off by using Control Panel
In Control Panel, click Programs and Features.
On the Programs and Features window, click Turn Windows features on or off.
In the Windows Features window, expand the Embedded Features node, and check or clear the checkbox for Unified Write Filter.
To turn UWF on or off by using DISM
Open a command prompt with administrator rights.
At the command prompt, type the following command to turn on UWF:
Dism /online /Enable-Feature /FeatureName:ISKU-UnifiedWriteFilter-or-
Type the following command to turn off UWF:
Dism /online /Disable-Feature /FeatureName:ISKU-UnifiedWriteFilter
Turning on UWF requires that you restart your device. After you restart the device, you must then enable UWF.
Enable or disable UWF
By default, UWF is not enabled. You can enable or disable UWF by calling the UWF_Filter.Enable or the UWF_Filter.Disable methods in Windows Management Instrumentation (WMI) class UWF_Filter, or by using the command line tool uwfmgr.exe.
You must restart your device after you enable or disable UWF before the change takes effect.
The first time you enable UWF on your device, UWF makes the following changes to your system to improve the performance of UWF:
- Paging files are disabled.
- System restore is disabled.
- SuperFetch is disabled.
- File indexing service is turned off.
- Fast boot is disabled.
- Defragmentation service is turned off.
- BCD setting bootstatuspolicy is set to ignoreallfailures.
You can change these settings after you enable UWF if you want to. For example, you can move the page file location to an unprotected volume and re-enable paging files.
Important
If you add UWF to your image by using SMI settings in an unattend.xml file, enabling UWF only sets the bootstatuspolicy BCD setting and turns off the defragmentation service. In this case, you must manually disable the other features and services if you want to increase the performance of UWF.
Configure UWF
All configuration settings for UWF are stored in the registry. UWF automatically excludes these registry entries from filtering.
UWF maintains configuration settings in the registry for the current session and for the next session after a device restart. Static configuration changes do not take effect until after a device restart, and these changes are saved in the registry entries for the next session. Dynamic configuration changes occur immediately and persist after a device restart.
To configure UWF at run time, you must use Windows Management Instrumentation (WMI) providers. You can do this in one of the following ways:
- Use the WMI providers directly in a Windows PowerShell script.
- Use the WMI providers directly in an application.
- Use the command line tool, UWFMgr.exe, which uses the WMI providers to modify the configuration.
- Use the Embedded Lockdown Manager (ELM), which uses the WMI providers to modify the configuration.
- Use ELM to generate Windows PowerShell scripts that use the WMI providers.
For more information about UWF WMI providers, see Unified Write Filter WMI provider reference.
For more information about the command line tool for configuring UWF, see uwfmgr.exe.
For more information about the ELM, see Embedded Lockdown Manager.