suddenly the data file damaged 9.5 GB.
Do you mean you have noticed a 9.5 GB data lose from your data file? What's the type of account configured in your Outlook? Is that a PST file or an Exchange OST file?
If you are using an Exchange OST file, we recommend you deleting that file and letting Outlook recreate it. Its generally faster to will resync the data from Exchange server.
If you are using a PST file, and if it is seriously corrupted. Try runing Scandisk.exe
(look under Programs | Accessories | System Tools) first, then
Scanpst.exe, repeating several times until neither program returns an error.
More reference:
http://www.slipstick.com/problems/pst-repair/repair-a-damaged-personal-folders-pst-file/
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
One more thing you should note is that lots of PST files are corrupted due to oversize, you should avoid keeping a lager PST file. Try to archive your mail datas regularly.
Regards,
Ethan Hua
TechNet Community Support