@ice We had this repeatedly at our old place! Ended up using a flexible butter knife to poke the latch. I got quite good at it.
Out of curiosity, after unplugging it and leaving it for a while, did you try plugging it back in and leaving it for a while again? *sometimes* that works to get it to unlock.
@gbrnt It has finally unlocked on its own! But it locks itself again every time I try to launch any program, with the same dreaded error I already encountered several times in the past. I'll guess need once again to unscrew everything and randomly clean every part I can reach until it starts to work again.
At least I can now run into the woods with (dirty) clothes.