DavidMSPeace wrote:

However, I see that in my archive calendar file most of the "Busy"
items are highlighted, regardless of age - except that one or two are
not. It is possible that when the latter were first entered these
unhighlighted events were not marked as "Busy" but, in order to try
to pick them out more easily retrospectively, I have subsequently
changed them to "Busy". However, they remain stubbornly
unhighlighted. Are they a lost cause?

What are the highlighting rules for the archive file?

What highlighting do you mean? The Navigation Pane summarizes your delivery
location calendar only, as far as I can tell.
--
Brian Tillman [MVP-Outlook]