On February 4, 1936, Mosolov was expelled from the Composers' Union for treating waiters poorly and taking part in a drunken brawl in Press House, a local restaurant. After this, Mosolov traveled voluntarily to the Turkmen and Uzbek republics to collect folk songs as a form of rehabilitation. His attempts were unsuccessful, and he was arrested on November 4, 1937, for alleged counter-revolutionary activities under Article 58, Paragraph 10 of the Soviet criminal code and sentenced to eight years in the Gulag. He served in the prison from December 23, 1937, until August 25, 1938. Glière and Myaskovsky had sent a letter to Mikhail Kalinin, the chairman of the Central Executive Committee of the Russian Soviet Federative Socialist Republic, arguing for Mosolov's release citing his turn towards realism, his "outstanding creative ability," and the fact that neither teacher had seen in Mosolov any anti-Soviet disposition. On July 15, 1938, Mosolov's sentence was commuted to a five-year exile—he could not live in Moscow, Leningrad, or Kiev until 1942. His quick release, having only served eight months of his eight-year sentence, was possible because he had been imprisoned not on political charges but on an overblown accusation of "hooliganism" brought by Mosolov's enemies in the Composers' Union.