Last updated: July 20, 2017
This issue is fixed in the latest updates.
To ensure that your calendars and email sync correctly, reconnect your Outlook.com account to Outlook for Windows. For detailed instructions, see Reconnect Outlook 2016 or Outlook 2013 to Outlook.com for uninterrupted email access.
Last updated: May 2, 2017
Currently, you can't use Outlook on Windows to edit calendars that are shared with your Outlook.com account, even if you've reconnected your Outlook.com account to Outlook. We're working to make it possible to edit shared calendars in Outlook 2016 for Windows.
I get an error when I try to accept a shared Outlook.com calendar using my Office 365 for business account in Outlook 2016
Last updated: May 2, 2017
When you try to accept a shared Outlook.com calendar using your Office 365 for business account in Outlook 2016, you might receive the "Something went wrong" error or your sign-in might fail.
To access the calendar shared with your Office 365 for business account, you’ll need to accept the invitation from Outlook on the web . If you've already clicked the Accept button in Outlook 2016, you won't be able to re-accept the invitation in Outlook on the web. The person who sent you the invitation will need to remove your permissions and then send a new invitation.
If you've been granted permissions to edit a calendar, you won't be able to edit or add items immediately after accepting. You will be able to edit the calendar about four hours after accepting the invitation. We're working on fixing this so that you can edit a shared calendar immediately after accepting the invitation.
If a tenant doesn't use Office 365 EOP filtering (the MX record points to a non-Office 365 endpoint), instant syncing will not occur. Instead, calendar syncing will only occur a couple of times per day. We're currently investigating how to enable instant syncing in these situations.
When accepting a shared calendar, you might see an HTTP 500 error. Select Accept again and Outlook should successfully accept the invitation. You will be redirected to the shared calendar. The team is working on a fix for this. If you see the error more than once, contact Support.
Currently, you can't see categories in shared calendars in Outlook on the web. This is a known issue that we are working to resolve.
When I edit a shared calendar in Mail for Windows 10, the edits don't appear on other people's calendars
Mail for Windows 10 does not prevent you from editing a calendar to which you only have read-access. However, any edits you make will only be local edits—other people who share the calendar will not see your edits.
Your calendar is linked to your Outlook.com account and not your connected account. Calendar invitations are sent from the account that's linked to your calendar.