Here is an simple way where you can easily Convert OST to PST file format in just couple of clicks. In this method you have to use this third party tool OST to PST Converter Software that can easily convert your OST file data into PST format in just simple clicks. With this tool you can easily repair corrupt OST file data and recover deleted or lost OST file data with all attachments. You can also try this software free demo version at free of cost.