A telephone answering device includes a digital recording and playback circuit for digitizing, recording and playing back a message from a telephone line; an audio random access memory for storing messages digitized by the digital recording and playback circuit; and a control unit, coupled to the audio random access memory. The control unit initially performs a test of only part of the memory in an amount sufficient to enable a user to perform predetermined basic functions, immediately after power is supplied to the device, without testing a remainder of the memory. Thereafter, a continuous repetitive series of tests of at least the remainder of the memory is performed while waiting for user input, to determine failed sections of the memory that are to be avoided during recording of a message. The failed sections of the memory, that are to be avoided during recording of a message after the determination, are marked. The user input is processed when it occurs, stopping performance of the continuous repetitive series of tests simultaneously with processing of the user input. The system returns to the step of performing the continuous repetitive series of tests after completion of the processing of the user input.