I have a customer whose using Office 365 and Outlook 2013.
They created a shared mailbox for shared messages.
Last week they discovered that it took hours to synchronize messages and folders from Outlook to Office 365.
On the forum I found the solution: Remove "Download Shared Folders" in settings.
After we did this, all mail and folders appeared immediately.
But this week they discovered that mail was missing from the Shared Mailbox.
It looks like the messages that were moved from their personal mailbox to the shared mailbox hadn't synchronized to Office 365, and now we couldn't find them again.
I managed to locate some messages, they were in "Recover Deleted Items", but the messages from the middle of July was missing.
Is there any way for me to recover these messages?