DIAGNOSIS The control box has a small internal battery that saves your memory settings when the desk is unplugged. If it loses power completely for an extended time (like during a move or a long power outage), that battery can drain and cause a reset.
FIX You just need to reprogram the presets. 1) Move the desk to your desired height using the up/down arrows. 2) Press and hold the 'M' button, then while holding it, press one of the numbered buttons (1, 2, or 3). You'll hear a beep. That height is now saved to that number. Repeat for your other preferred heights.
IF THAT DIDN'T WORK If the memory resets happen frequently while the desk remains plugged in, there could be a loose connection intermittently cutting power to the control box's memory circuit. Check all the cable connections at the control box and keypad, as described in the 'won't turn on' fix. If it persists, the control box itself may be faulty.
HEADS UP It's a good habit to note your preferred heights (in centimeters or inches) somewhere, just in case this happens again. That way you're not guessing where your perfect ergonomic spot was.