How to fix the squeaky high pitch sound in my Acer Nitro 5 keyboard's space bar?

batmalin said:

Well, I don`t se any other solution than replacing the key. https://www.replacementlaptopkeys.com/acer-nitro-5-keyboard-key-replacement/

This is probably long solved by now, but you DO NOT need to replace the key as your first port of call. 
The best thing to do is lift it up to gently clean underneath, which I did with a microfibre cloth. To do this, lift up the key from the top. For a key like the spacebar I would recommending using the index fingers of both hands and slowly pulling up the key. It requires moderate force, but don't brute force it, just slowly keep pulling until you hear it pull up. It will then open up, with a hinge on the lower part of the key. Clean it carefully and then press back down on it, making sure to spread the pressure by using multiple fingers just in case. It's unlikely that it would cause damage to your laptop casing to be less gentle, but it's better to be safe than sorry. Eventually it'll snap back into place.
Since doing this, mine hasn't squeaked once. Definitely worth trying this before sending it off to be fixed (no point having this mentioned on the warranty at any rate) or spending $14 on a new spacebar key. Hope this helps!