The most effective and best methods to convert OST to PST for MS Outlook is EmailsGuru OST to PST Converter. It allow users to convert OST file to PST format. This tool preserves all email data, including attachments and folder structures during the conversion process. It is capable to fix corrupted or damaged OST file and convert them into PST format. Moreover, it can convert OST file to PST with or without installing Outlook in your computer.