We had a co-worker come to us asking if it was possible to recover some email messages she had accidentally deleted using shift+delete, which skips the trash folder entirely. I’m not sure how one accidentally presses two keys that really aren’t next to each other and happens to delete important emails, but I have learned not to ask. I googled it and came up with a simple solution.
1. Exit Outlook.
2. Open the Windows registry editor.
3. Browse to My Computer\HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\Client\Options.
4. On the Edit menu, point to New, and then click DWORD Value.
5. Type the name DumpsterAlwaysOn.
Note Do not type any spaces in the name.
6. Set the DWORD value to 1.
7. Restart Outlook.
The Tools menu now has the Recover Deleted Items command for every Outlook folder.
Source: Microsoft Office Online