The article is an attempt to define the legal nature of the action under Article 791 § 2 k.p.c. to establish, that the writ of execution cannot be enforced. The purpose of this action is defense against execution performed under the writ of execution enforceable erga omnes (against all). We also analyzed the legal nature of the judgment passed in consequence of the allowed action, as well as the usefulness of action under Article 791 § 2 k.p.c. for the protection of the rights of the parties to the execution proceedings, particularly in the context of the availability of actions under Article 840 and 841 k.p.c.