“Sync Issue” messages, especially “Conflicts”, can pile up in Exchange mailboxes when Outlook is used. There is a server-side method of handling this:
- In the Exchange console, under Organization Configuration, under Mailbox,
- Create a Retention Policy Tag, tag type Sync Issues, age limit 3 days. Set Action to Take as Permanently Delete.
- Create a Retention Policy using the above Tag. Add any or all involved mailboxes, to it.