If you have deleted the folder and emails permanently by pressing Shift + Delete keys, or deleted them from the Deleted Items folder again, you can still recover items that's been permanently deleted. When you delete an item it's marked as deleted and the space it occupies is marked as 'reusable'. And as long as the space isn't reused for another item, the information can be recovered. If you have received any new email or perform some actions with your mailbox, the loss of your deleted emails may be permanent. Follow the steps in this guide to recover permanently deleted emails and folders that are no longer in your Deleted Items folder.
1. Close the Microsoft Outlook and other applications that may use your mailbox
2. Download, Install and run PST Walker email recovery
3. Open the Outlook (.pst) or Exchange mailbox (.ost) with PST Walker
4. Check “Find “hard deleted” and “orphaned” items ” checkbox
5. After the recover process, select “All Hard Deleted Items” folder in the “All Folders” pane
*Please note when you accidentally delete a folder in the Outlook, it's first move the emails from this folder to the Deleted Items folder, and then delete the folder and the moved emails in the Deleted Items folder.
6. Click "File"->"Export" to save recovered deleted emails and folders