FBWF (File Based Write Filter)

As opposed to the EWF, the FBWF operates at file level. This makes it possible to define possible exceptions and to allow write accesses to individual files or folders. All other write accesses are redirected to the RAM. Following a restart, the system is returned to its original state.

As soon as the FBWF is activated, some folders are released for direct write access. For example, the folder C:\Data is available for writing permanent data. Through the release of the folder C:\TwinCAT\Boot, a new TwinCAT boot project can be loaded to the computer without having to deactivate the FBWF first


FBWF (File Based Write Filter) 1:

Do not run EWF and FBWF at the same time

If both write filters are activated, the FBWF exceptions will be intercepted by the EWF and will be lost when the computer is restarted.

Do not activate the two write filters EWF and FBWF at the same time.

In most cases the FBWF is the better choice, as it is simpler to operate and allows direct write accesses. However, there are scenarios in which the EWF is indispensable, e.g. HORM (Hibernate Once/Resume Many) is not supported by the FBWF. In addition, the use of compressed NTFS volumes is not possible with the FBWF.

Control with the Beckhoff FBWF Manager

The FBWF is controlled by the Beckhoff FBWF Manager software, which is already installed by default.

FBWF (File Based Write Filter) 2:
Beckhoff FBWF Manager, user interface.
Key to Beckhoff FBWF Manager.




The FBWF is switched on or off by the Change State button. The current and next states are displayed. Changes are only ever accepted after a restart.


Compression can only be activated when the FBWF is active. Indicates whether the compression of the FBWF overlay is active.


PreAllocation can only be activated when the FBWF is active. Indicates whether the PreAllocation is activated.


Exclusions are created on the Exclusion Settings tab. When an FBWF is active, folders are added to the exclusion list by default.


Activate the FBWF as follows:

1. Start the Industrial PC or Embedded PC and click Beckhoff FBWF Manager under Start < All Programs < Beckhoff FBWF Manager.
2. Click the Change Settings button on the General Settings tab.
3. The Next State display changes and the message FBWF ENABLED appears.
4. Restart the Industrial or Embedded PC.
The changes are only active after a restart. The display Current State changes after the restart to FBWF ENABLED. You have successfully activated the FBWF.