Most of the times if we have deleted any email from outlook ( Specifically hard deleted), we are forced to believe that it cannot be recovered without restoring from backup, which is not completely true.

We can recover any email deleted/ Archived from the Mailbox if it has not passed the deleted item retention period ( which is by default 7 days)

A few tips that I follow

1.       Any Item deleted from the Mailbox either a soft delete or hard delete goes in the dumpster which can be recovered unless the online maintenance has not cleared those emails ( in default case if the mails were deleted on 31st  Oct. they will not be actually gone from the database till 7th Nov)

2.       Emails which are soft deleted goes to the deleted items folder , on which we have the dumpster enabled by default & that is the reason we can recover anything which is deleted from deleted items during 7 days period.

3.       If we have hard deleted any items from Inbox, on which the dumpster is not enabled, we normally cannot recover those items from “Recover Deleted Items” option. However if we enable the “DumsterAlwaysOn” registry after we hard delete an item, we still can recover those. The deleted item is still there just not visible to us. & adding the registry would make that visible to us.

4.       If you move an item to PST after it has shown up in your Mailbox, they also can be recovered if the PST is lost /corrupted, Since when we move an item to PST it is copied to the PST & then deleted from the mailbox

5.       If Mailbox Manager policy deletes any email from your Mailbox by error, this also can be recovered through the above means.

 Conclusion:
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Any email which is deleted by any means / Archived / Moved to PST is still available in the dumpster for recovery unless it pass the “deleted Item retention period”

 If you have to do this from the server side you can use exmerge to recover data ( choose option to recover data from dumpster)