Has been observed how in some situations the Outlook Calendar is showing a weird behavior consisting in:
- Autonomously deleting the meeting invitations and/or confirmations
- Autonomously accepting or declining the meeting invitations
- Sending the same meeting invitation to the same attendees in loop
- Sending duplicate meeting invitations
- Sending the meeting confirmation over and over again
Those issues are most often (but not always) due to how external devices’ protocols communicate with the Exchange server.
In fact, if the meeting organizer or one or multiple attendees are synchronizing their calendars on their smartphones or external devices, the synchronization would typically be handled by a network protocol developed by Microsoft called Exchange ActiveSync.
In such scenario “weird” calendar issues might be expected.
What is Exchange ActiveSync?
Exchange ActiveSync is a network protocol responsible for synchronizing a mobile device with the Exchange mailbox and calendar Items. It allows mobile users to access to their email, calendar, contacts and tasks from their external devices.
Simply many mobile OS versions (Windows included)do not play nice with Microsoft ActiveSync, generating a wide range of weird calendar issues.
Let ‘see how to address them.
1) Outlook.exe /Cleanreminders
It deletes and regenerates the calendar reminder notifications
Click on Start >> On the search box type: Outlook.exe /Cleanreminders, and click enter.
Outlook will flash out for a couple of seconds to perform the task.
Restart Outlook, and check if the issue persists.
1) Delete the meetings.
The meeting will need to be deleted from both sides, the meeting organizer and the receiver.
It will be necessary to delete the meeting from:
- The Outlook 2013 client Software
- The Mail application synchronizing the mailbox to the external device
- Outlook Web App Calendar.
Right click on the meeting invitation, Cancel Meeting.
1) Log out from the Mail application on the External Device.
If the issue persist, the meeting organizer (or the attendee who is accepting, declining or updating the meeting over and over in loop) will need to temporarily log out from their mail application installed on their smartphone.
This will help to narrow down the possible root causes and confirm if the problem is caused by Exchange ActiveSync.
Most probably the issue will disappear once the mobile Mail application has been logged out from the phone.