This specifies the maximum number of processes for the HTML
Engine, so the value depends on the selected engine. You can
to avoid getting an exception for non-application of
The initial value comes from registry value HtmlProcessPoolSize if
the engine supports a variable number of processes. Changes made to
the property value affect only the specified engine and are not
propagated to the registry.
For the MSHtml engine, the property value is always 1 because
the out-of-process execution (see registry value MSHtmlBootstrap) only
supports 1 process. Attempt to set this property for the MSHtml
engine will cause an exception.
For the Gecko engine, the property value is fixed after the
process pool has started. Attempt to change the property value for
the Gecko engine while the process pool has started will cause an
For the Chrome engine, the property value specifies the upper
bound of the number of processes for creating worker processes.
Decreasing the property value below ProcessCount does not terminate existing