Menu path: Setup > System > File Based Write Filter

The File Based Write Filter (FBWF) is the system's own write filter for Windows Embedded Standard.

A detailed description of the FBWF function can be found at

The write filter protects the system against accidental changes or deletions and harmful software. You should (re)activate the filter after setting up the system, for example after installing your own applications or making changes to the Windows system outside the IGEL Setup. Changes in the IGEL Setup or via the IGEL UMS management are not blocked by the write filter.

FBWF status display in the taskbar

  • fbwf-on_crop Red symbol: FBWF disabled
  • fbwf-on_crop Green symbol: FBWF enabled (default setting)

Settings in the IGEL setup

  • Toggle FBWF

    The write filter is enabled and protects the system against changes.

    The write filter is disabled.

  • Enable the compression of the overlay

    The write filter's cache will be compressed in order to save storage space.

    The write filter's cache will not be compressed.

  • Threshold for FBWF: Figure in MB, max. 1024 MB, the default setting is 64 MB
  • Excluded directory: The directories in this list are writable, even if the write filter is enabled. This is suitable for configuration files or the signatures of a virus scanner for example.

    Do not change or delete the entries initially present in the list. Otherwise, the system will no longer run in a stable manner.

    The FBWF must be enabled during regular system operation! Disable the write filter only temporarily, for example for administrative duties. IGEL does not support permanent operation with the write filter disabled. Directory exceptions must be defined as specifically as possible in order to ensure the greatest possible protection for the system in spite of the exceptions.