Devany wrote:
On an internal door, the deadlatch does not fully retract into the
door when the handle is turned. It protrudes about 5mm and fouls the
strikeplate when trying to open the door.

There are several of these in my house which are starting to get right
on my nerves.

What is the problem?

They are simply worn.

I guess I could chisel out the strikeplate, but I know I'm crap at
doing that. Shouldn't the deadlatch retract fully? I can't see that
wear and tear would affect it that much. Would a new handle fix it?

Don't bother digging the chisel out of the tool box, just find out whether
it's the handles or latch that's worn and change the offending item - or
both handles and latch if you wish.

Falco