Situation: The user receives this message when she opens Outlook:
‘Your mailbox has reached its maximum size limit at which you cannot send or receive any more content. Empty your deleted items folder from MS Outlook or delete messages from your mailbox to create more space.’’.
Resolution: We can reduce the size of Outlook Data Files by using Mailbox Cleanup tool and Conversation Clean Up tool. Please refer to this post for more details:
in our case, we find the user has many other users’ mailboxes in his Outlook. removing these or some of users’ mailboxes, that reduce 30 GB size.