Mac not copying and pasting between applications Today, I found when I copy from one application into my clipboard, the clipboard cannot be pasted into another application.

The next application has its own clipboard.

If I paste into the first application I see what I just copied.

If I paste into the second application I see what I copied perhaps an hour ago.

So, clipboard copy and paste has become application specific.

How do I turn this off?

Thanks.

EDIT, I'm on Mac 10.13.6, and I could not copy between Firefox and Chrome. Rebooting cured the problem.
I had no helper applications installed.

Since upgrading to Mojave, this issue has not reoccured.