Scheduling and managing events using Outlook.com calendar
Hi SvenKndler-3111,
I'm sorry to hear that you've lost all of your calendar appointments. I can certainly understand how frustrating and concerning that must be, especially when important scheduled events disappear unexpectedly.
As this is a community forum, our ability to investigate account-specific or backend service issues is very limited. Community members and moderators do not have access to Outlook.com servers, mailbox data, or recovery tools beyond the troubleshooting steps already available to users.
If you've already worked with Microsoft Support and they were unable to identify a solution or restore the missing appointments, then unfortunately there is nothing further that we in the community can do from our side. Based on your description, this appears to be beyond the scope of community support.
If the issue is related to a temporary server-side problem, synchronization issue, or an ongoing service incident, it may be worth checking again over the next day or two to see whether the calendar data reappears automatically.
I'm sorry that we can't offer a more direct resolution in this case. Thank you for your understanding, and I hope the appointments are restored once the underlying issue is resolved.