For those of you who may encounter any type of error messages when restoring
a back up file of Outlook.pst, I recommend the following which have worked
for me.
Go to 'Start' menu and click on 'Search', when that opens, type in the file
and folders field, 'Scanpst.exe'. This is a utility program that repairs
errors with all Outlook related files and folders. Once the search has
located it, simply click on it and when it opens, click on the 'Browse'
button to search for the specific 'Outlook.pst' file. Once located simply
follow the prompts and it will repair any errors with the file so that you
can import it into your current Outlook personal folder.
Finally, if all still fails, then I suggest going to this site and
downloading an Outlook Repair Program which will do the job. See
http://www.recoverytoolbox.com/outlook.html
All the best!