Currently the setting Continue is the default setting when the save operation encounters parts that Creo Parametric thinks need to be modified upon regeneration. "Make read only" is not available as a default setting.
PTC, please allow "Make read only to be set as default. Also, fix the failure on save problem when objects are marked as read only on the fly.
Setting the value of "Make read only" as a configs option for dm_checkout_on_the_fly in Creo Parametric