Environment:

Office 2013 Suite
Windows 7

Few of our employees setup a calendar event on their calendar and invited about 6-10 attendees.  When few attendees have replied with an acceptance of the event and the others have yet to reply.  5 of the group that have replied is somehow sending the same acceptance reply repeatedly.  This has been going on for several days now and the timing is seemingly random.  Obviously the person that sent the acceptance reply is not manually doing it repeatedly.  That would be too easy of a solution:)  Can someone please help me troubleshoot this problem.

Thanks.

Hi,

Does this issue happen to all calendar events? If so, we may try to create a new event using OWA and then check if you can reproduce the issue.

Do you have any delegates set for these affected users?

Do the employees have their calendars sync with any mobile devices? If so, we may disable the sync to see if the issue will be fixed.

In addition, we may try to enable Outlook troubleshooting logging on the calendar owner's computer and delegate computer, then we can check the logging data to see if we can find if the responses are sent by a delegate or third-party software. To enable Outlook troubleshooting logging, go to File > Options > Advanced, scroll to the bottom of the dialog and select the "Enable troubleshooting logging" option. You'll need to restart your Outlook to trigger the logging. For more information about Outlook troubleshooting logging, please refer:

https://support.microsoft.com/kb/2862843

If you have trouble reading the log file, you can share it to us via sending it to GBSD TN Office Information Collection  ibsofc@microsoft.com. The subject of the message should be the thread link.

Regards,

Steve Fan
TechNet Community Support