Mont. Code § 33-22-208
"Notice of Claim: Written notice of claim must be given to the insurer within 6 months after the occurrence or commencement of any loss covered by the policy or as soon after that date as is reasonably possible. Notice given by or on behalf of the insured or the beneficiary to the insurer at .... (insert the location of the office that the insurer may designate for the purpose) or to any authorized insurance producer of the insurer, with information sufficient to identify the insured, is considered notice to the insurer."
"Subject to the qualifications set forth below, if the insured suffers loss of time on account of disability for which indemnity may be payable for at least 2 years, the insured shall, at least once in every 6 months after having given notice of the claim, give to the insurer notice of continuance of the disability, except in the event of legal incapacity. The period of 6 months following any filing of proof by the insured or any payment by the insurer on account of the claim or any denial of liability in whole or in part by the insurer must be excluded in applying this provision. Delay in giving the notice may not impair the insured's right to any indemnity that would otherwise have accrued during the period of 6 months preceding the date on which the notice is actually given."
§ 33-22-208, MCA