How do I cut an object?. Whatever I do just makes the whole object disappear

[Jonah Jones]

I can't cut objects.  I use the knife tool, make the cut and the whole object disappears and is reduced to squares.  I then select the move tool and try to separate the two, then the selection squares disappear too.

[R C-R]

This works fine for me in Affinity Designer version 2.0.3 on my Mac. If it is not for you, can you tell us which version you are using, if you are on a Mac or Windows computer, & what kind of object you are trying to cut apart?