[Please check the updated version of this post here]

For Windows 7 desktop users :

• Exclude all files present in  both below directories:
• %userprofile%\Application Data\Microsoft\Outlook
• %userprofile%\AppData\Local\Microsoft\Outlook

• Or exclude *.nk2, *.dat, *.srs, *.xml, *.otm, OutlPrnt, *.ost, *.tmp, *.obi, *.dat and *.oab files from these directories