DIAGNOSIS You don't need to remove the whole back panel. The filter is designed to slide out from the side, but the fit can be snug and isn't super obvious at first glance.
FIX Unplug the unit first. Look at the right side of the Cube (if you're facing the control panel). You'll see a small, recessed notch or a textured area along the vertical edge. Firmly grip there and pull that entire right-side panel straight outward. It's one piece that covers the filter compartment. Once it's off, you'll see the white foam filter. Just slide it out. You can rinse it under lukewarm water, let it air dry completely (this is crucial), and then slide it back in. Snap the side panel back into place until it clicks.
IF THAT DIDN'T WORK If the side panel won't budge, double-check you're pulling from the correct side (the one without the control panel). Sometimes a thin plastic pry tool or a butter knife (used gently) in the seam can help get it started. Don't force it upward or downward—it pulls straight out.
HEADS UP Never run the dehumidifier without the filter, and never put it back in damp. A wet filter can mold and will restrict airflow, which can lead to bigger problems like the unit freezing up or overheating.