A possible reason for this message is that the probes cable has come unplugged from the meter chassis. If this is the case, you may notice that you can get the "Or" message to go away by jiggling the cable a bit where it feeds into the chassis.
To reconnect the wire:
1. Turn the meter off
2. Loosen the small black nut where the wire feeds into the meter by turning it counterclockwise.
3. Loosen the larger cream colored cap on the chassis by turning it counterclockwise until it comes completely off the meter.
4. Press the connector securely onto the socket prongs.
5. Turn the meter on and wait to see if the "Or" display is gone. It should read "000".
6. If you still get the "Or" display pull off the connector off the prongs, rotate it 180 degrees, and reconnect it. It should now read "000".
7. Reconnect the cream-colored cap and then tighten the black nut.
If LCD still reads "Or", the probe needs to be replaced. Contact Spectrum Technologies