copy and paste doesn't work

Also with the key combination cmd+c and cmd+v ?

Or with which menu ?

I have a keyboard with a similar problem.

The command key works and the "C" key works, but command+C doesn't work (doesn't copy).

It's not a conflict with another shortcut because the same commands work with another keyboard connected to the same machine.

This has been tried in 3 different Macs and the bad keyboard always cause the same problem in all of them, and none of them has the problem with other keyboards.

Pretty weird...

Does anyone know how to debug this?

Well, you have two options if the cmd+c and cmd+v doesn'r copy and paste. You either have a keyboard problem or your Mac motherboard is damage. If that's the case you have to spend some little money.

1. Get the keyboard replaced, or

2. Get another new Mac machine

try using the other command key (right of the space key). That worked on my problem (command+V didn't work with left side command key).

try using the other command key (right of the space bar).