Look at the LED light next to the SMART/LEARN button on rear of the motor unit. You may need to remove a light lens cover in order to see it. If the light is flashing rapidly this means you have a stuck button on one of your remote controls. Take the batteries out of each remote control. When you remove the batteries from the bad remote, the light will stop flashing. This remote needs to be replaced. If one of your neighbors remote controls is inadvertently programmed into your receiver, you door will open when their remote is activated. If this happens you will need to clear out your receiver and reprogram your remote controls. Press and hold the smart/learn button for 6 seconds or until you see the small LED light near the button turn itself off. If the above steps have been followed and the symptoms continue, there may be an electronic short in either the wall control button or the receiver logic board. In this case, remove the wall control wires from terminals 1 and 2 on the motor unit. Should the symptoms persist after the wires are removed, replace the receiver logic board. If the symptoms stop with the wall control wires removed from the motor unit, replace the wall control button, and the wires leading to the wall control button.

I know this is an older thread now but this is frustrating. I have two garage doors with Craftsman 1/2HP 41A5021-2F Red button type. Both are now messed up and will only program one opener. I reset and can program any one of the 4 remotes (only one button) to the door but will not learn anymore. Reset again and i can program another but I CANNOT program more than 1 button of 1 remote to a door. Prior to this i had 4 three button remotes and each door had a key pad entry system. I am now up the creek without a paddle! I have even unplugged the units for hours and still the same behavior!!!

Make sure the lock function on the wall control is on. If the light in the wall control is flashing press and hold the lock button for about 3 seconds.

Sure sounds like they have changed the radio frequency. That is the only reason they all would not work.