FolderBind is an Exchange Online mailbox audit record. It indicates the time when a non-owner accesses a mailbox folder. You could report the problem as a support issue to Microsoft to make sure that it gets recorded. It’s the only way the engineering team will spend any time considering the issue.

A good idea thanks. I tried that and it seemed to be missing. ChatGPT and its friends seemed to hallucinate trying to track down an opperation called FolderBind but it didn’t uncover anthing. I would have thought it would have been a basic audit event to know if someone was adding open calendars in your organisation in the hope of gaining advantage they perhaps shouldn’t have. Thanks

Whar I do to find new audit events is to perform the action I want to know about, wait 3 hours, and then search the audit log for my userid and the approximate timeframe when I performed the action.