User283571144 posted
Hi geoffHome,
According to your description, I suggest you could try to go to Tools>Options and there to Environment>Keyboard. Type into the text field with the title "Show commands containing:" the term "StepInto". This filters the list below.
Select "Debug.StepInto". Check if F11 is registered for "Global".
More details, you could refer to below image:

If you have already set the F11 as global, I suggest you could create a new project to test F11 is work well.
Best Regards,
Brando