Totally lost playing on PC with keyboard and mouse. Trying to get the knife in the entry hall and the instructions aren't helpful. If I hit enter on the knife a box on the right says move but it won't let me do anyhting with the keys. If I click the move box it goes away, if I click the knife with the mouse nothing happens. How do I move it to my inventory?

I am having the exact same problem with the game if anyone can help that's great.

I had the same problem, too. Following the instructions simply did not work. There was nothing I could do, so I quit. Then I tried again today, and this time it did work. Seems like it's a bug that happens sometimes - but apparently often enough, because there's a whole thread several pages long over at the Steam forums about the same thing.

I realise this thread is old, but I just dragged and dropped the knife in my inventory with the mouse and it was added fine. Then, from the inventory, I selected the knife, clicked 'Equip' and there I was, armed and ready.

Not sure whether this is a new update or it was already a feature though.