Why doesn't my stderr redirection end after command finishes? And how do I fix it?

Question

In Windows, either in command line or a batch file, the command DIR 2>NUL: 3>&2 (you can replace DIR with anything, even if isn\'t a file

Answer 1

The problem is with 3>&2. File descriptor 3 isn't valid, and it appears to upset Windows in some way. Leave it off, you don't need it.

See Microsoft's documentation (archived) for the full treatment.