This will sound strange, but it works!!!

Important!!
Since we will deliberately corrupting the PST file, I strongly suggest that you make a copy of it first!

Step 1
Download a free ‘HEX Editor’. I’ve used the HDD HEX Editor.

Step 2
After making a copy of your PST file, open it with the HEX Editor. Delete the positions (using the space bar) 7 through 13.
(00007 – 00008 – 00009 – 0000a – 0000b – 0000c – 0000d – 0000e – 0000f – 00010 – 00011 – 00012 – 00013)

The HEX Editor will display the code “20″ for each position deleted.

Once done, save your PST file. It is now corrupted.

Step 3
Now, open up the ‘Inbox Repair Tool’ (scanpst.exe). The program is usually stored here:
C:\Program Files\Common Files\System\Mapi\1033\NT

The program will scan the PST, then make a backup. After the backup is done, it will repair the PST file.

For more information about this program, see: Microsoft Knowledge Base article 287497.

Step 4
Once complete, you can open the PST file with Outlook, and you will find your deleted emails have been restored!