With this setting you can tell &xwp; not to use its background "Worker" thread for certain features.

Important note: Many of &xwp;'s features RELY on this thread. Enabling this setting will severely limit &xwp;'s capabilities; see "The Worker thread" for an explanation what the Worker thread does. All those features will no longer work when this setting is enabled.

This setting is only meant to be a "last resort" in case &xwp; does not work properly on your system.