Under CCP 1094.6, a petition for administrative mandate must be filed within 90 days after the administrative decision becomes final. But that statutory period does not begin to run until the administrative agency mails its decision to the petitioner with a notice that warns of the 90-day limit on petitioning for mandate and states the date on which the administrative decision became final. Here, the agency’s notice contained conflicting statements about finality of the decision, saying in one place that the decision was final on the date the notice was mailed but in another than it would become final 90-days later. Due to the ambiguity in the notice, the pro per petitioner was entitled to proceed with his petition which was filed more than 90 days but less than 180 days after the notice was mailed.