A hearing aid comprises a microphone, a sound transducer, an amplification signal path configured for coupling the sound transducer to the microphone; and a circuit configured for completely or partly blocking the signal path during a comfort delay period, which may be adjustable, when the hearing aid is switched on. It can hereby be avoided that the hearing aid transmits a disturbing howling tone during the period until it is placed correctly at or in the ear of the user, if the user switches on the hearing aid before it is correctly positioned. The circuit is further configured for generating and transmitting a special acoustic signal to the sound transducer during at least a portion of the comfort delay period. In this way a user will be able to ascertain whether the hearing aid is switched on and that it functions as it should.