(1) A foreign corporation may not do business in this state until it registers with the secretary of state under this part.
(2) A foreign corporation doing business in this state may not maintain a proceeding in any court of this state until it is registered to do business in this state.
(3) Except as provided in subsection (4), the failure of a foreign corporation to register to do business in this state does not impair the validity of a contract or act of the foreign corporation or preclude it from defending a proceeding in this state.
(4) A contract between the state of Montana, an agency of the state, or a political subdivision of the state and a foreign corporation that has failed to register to do business as required under 35-14-1505 (4) is voidable by the state, the contracting state agency, or the contracting political subdivision.
(5) A limitation on the liability of a shareholder or director of a foreign corporation is not waived solely because the foreign corporation does business in this state without registering.
(6) Section 35-14-1501 (1) applies even if a foreign corporation fails to register under this part.