Minn. Stat. § 514.42: TERMINATION OF LIEN.

The lien shall cease unless said statement be so filed within 30 days after the termination of such labor or service, unless the same shall have been wholly performed between October 1 and April 1 next thereafter, in which case the statement may be filed on or before the last day of said April. Such filing shall continue the lien in force for 90 days thereafter, and no longer, unless within that period an action be commenced for its enforcement as provided in sections 514.40 to 514.58.