When I copy text from the terminal, I can paste it into the terminal with no problem. I can also paste it into Firefox or TextEdit.
When I try to paste it into my Apple Mail, I get:
Mac OS Extended (Case-sensitive, Journaled)
This is something I had in my clipboard a while back—days ago. That day, I was having trouble pasting into Firefox when I copied from Terminal (and instead got the same text noted above). But it doesn't seem localized to Terminal after all.
Right now when I copy text from Apple Mail, I can paste that text back into Apple Mail or into anywhere else. But text copied from anywhere but Apple Mail can't be pasted into Apple Mail; attempting to do so will instead paste into Apple Mail the same text that was last copied in Apple Mail.
I don't even know where to start to try to debug this or see what is causing it. How can I fix this?
(I'll post the output of any diagnostic commands that anyone can suggest.)