We have an EWS managed API application that creates appointments in Office 365. We just noticed that appointments with a recurrence on them start one day earlier. This never happened before. And it only happens in central and pacific time zones. We process in eastern time zone and it works ok. Normal appointments work fine in any time zone.

When we debug, it shows the correct start date and time zone but when we view it in Outlook or OWA it starts one day earlier. This is not an all day event.

Is this a new feature or a bug? If it is a feature then we will subtract a day from the start on recurring items for any office 365 user.

Any one else have this issue? It just started doing this or we just caught it recently.

• Edited by Gary Cawley 15 hours 53 minutes ago

If it is a bug then it should be reproducible (outside of your code base) so the place where I suggest you start is create a simple example that you (and more importantly Microsoft) could run outside of your application. If you can reproduce the issue with this then post the code to the forum (or probably better at that point contact Microsoft support about the bug).

The other suggestion I would have is look at the Appointments with MAPI Editor like mfcmapi or OutlookSpy and compare the datetime value that get set when you create Appointment in Outlook/OWA to what happens in your application. (AFAIK OWA uses EWS to create appointments so if it doesn't happen in OWA but it does in your code then I would look further for an issue with your code)

Cheers
Glen