Hi there. If you are transferring a toner from another printer it will not clear the toner life end message. This is because the toner contains a reset gear which activates a reset switch in the printer when first used but then it immediately rotates to prevent the cartridge from being re used in another printer or refilled. Hence if you fit an already activated cartridge to another printer it will not reset the warning.Provided there is enough toner in a transferred cartridge that is does not activate the low toner sensor, then you can clear the end of life message as follows manually.1. open front cover where toner inserts2. press the "clear/back" button. It may display "replace drum?". Do not respond to this.3. press *00. A message "accepted" will be displayedThe toner warning should then be cleared.