[Darryl Ramm]

All I can think if is try trashing prefs and test with a new empty session in case the session is corrupt.

Mistakes I can think of are not having a timeline selection because link edit and timeline is not selected. Or something like you have dynamic transport with play start past the selection. Or maybe having loop record selected instead of loop play.

If the blue play in and out markers show up correctly around the timeline selection and the play button shows loop play it should just work...