The settlement of investment disputes between the investor and the host government due to the violation of the investment treaty is subject to the rules governing the dispute settlement clause under the relevant treaty. Among these criteria is the condition of the Cooling-Off Period, the observance of which as a form of jurisdictional procedure and a prerequisite stage for dispute resolution, is directly related to the jurisdiction of courts or arbitration tribunals. According to this condition, the claimant of an investment dispute should refrain from filing a lawsuit in court for a certain period. The parties should do their best to resolve the dispute amicably. The main question of the research is, what will the effects and results be if the investor or the host government does not comply with the waiting period? Different courts have different opinions in this regard, according to some, non-compliance with this condition has no effect on the jurisdiction and is an optional procedure, while others emphasize that it is mandatory and effective in the court's jurisdiction and even the possibility of compensation. The review of the authors with a descriptive and analytical approach shows that determining whether this condition is mandatory will depend on the review of the text of the treaty, the rules governing the relevant investment, and the extent of the language of the text.