If it is the BeoSound 9000 it may mean there is too much dust on the two clear safety pins.
Page 34 of the BS9000 reference book says -
If dust builds up in the opto-coupling devices, the CD carriage will slow down, and the cue
‘CLEANING REQUIRED’ appears in the BeoSound 9000 display.
Normal maintenance, such as cleaning the BeoSound 9000, is the responsibility of the user. To achieve the best result, please follow the instructions. Do not use alcohol or other solvents to clean any part of BeoSound 9000!
Surfaces - Before you start cleaning BeoSound 9000, we recommend that you open the glass door and then switch off the mains. In this way all surfaces are accessible for cleaning. Use a soft, dry cloth to wipe dust off the BeoSound 9000. To clean the surfaces, we recommend that you use a mild window cleaner.
CD mechanism - The circuit controlling the movement of the CD carriage has a built-in safety function which protects your fingers, etc. from being hit by the fast moving carriage. This circuit depends on light/reflections, and works via opto-coupling devices built into the two small ‘pegs’ (A). When the glass door is opened, or if something interrupts the light-circuit, the carriage slows down in speed, and finally comes to a halt. Over time dust may build up and thus reduce the light emitted to and from the opto-coupling devices. Dust particles on the inside of the glass door may also cause extraordinary reflections which may be interpreted by the safety function in a wrong way. So, in order to prevent malfunction of the safety circuit, we recommend that you wipe dust off the two pegs (A) on a regular basis. Likewise, when cleaning the surfaces of BeoSound 9000, remember also to clean the inner surface of the glass door.
Hope that helps
Stoobie