In January 1933 the National Socialists took power and lost no time in transforming Germany into a one-party dictatorship. With political party membership now illegal (other than membership of the National Socialist Party), she terminated her party membership. Olga Brandt-Knack's record as an active SPD member nevertheless led to her being classified as "politically unreliable". The Hamburg State Opera was terminated her employment and she was obliged to give up the dance school she was running. She was later placed under surveillance by the security services and, on at least one occasion, briefly arrested. Unable to work professionally, she now, like her sister, took a job as a surgery appointments clerk till 1942. Between 1942 and the war's end in 1945 she moved out of the city and lived quietly with friends in the countryside.