From: Mooins on
If you have Win 7 and you use the Microsoft Personal Folders Backup app in
Outlook 2007 you may get a message saying something like Cannot find outlook
backup.pst. The problem is that Win 7 places these files in a different
location than in Win XP or earlier versions.
The problem is fixed by opening the backup utility (file\backup...) then
clicking the Options Button. Click the Browse... button and point it to the
following location:
C:\Users\Your Logon Name\AppData\Local\Microsoft\Outlook\Outlook Backup.pst.

("Your Logon name" is a placeholder for your logon name or the actual User
of the computer)

Click OK. You should then be able to do a backup
From: wandong on
You can try a tool called Advanced Outlook Repair. You can download a free demo version at http://www.datanumen.com/aor/aor.exe . I think it is a useful repair tool for you. It is easy to recover your PST file by using its wizard. It is a powerful tool to recover messages, folders and other objects from corrupt or damaged Microsoft Outlook PST files.

Detailed information about Advanced Outlook Repair can be found at http://www.datanumen.com/aor/
.
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