Notice something funny with this sentence? Correct. At a first glance it does not make much sense. It probably should read:
This appointment occurred in the past.
Well, unfortunately the case is not quite as straightforward. This is actually an Microsoft Outlook error message, given when creating or accepting a new meeting with a meeting time set prior to the current time. So unless one is, for reference’s sake, updating one’s calendar with a meeting that did in fact take place, use of the word ‘occurred’ is not appropriate because the meeting has in fact not yet taken place.
However, that still does not mean it is acceptable to say “This appointment occurs in the past.“. Instead, how about this:
The scheduled time for this appointment lies in the past.
Given that MS Outlook clearly is geared towards business use, it should go without saying that its messages should adhere to proper grammar.