Microsoft OST to PST Converter - Version 3.7 Microsoft OST to PST Converter tool is email recovery tool to recover mailbox from Offline Storage files (.OST). OST to PST conversion important because OST file cannot open. Microsoft OST Recovery software recovers important component of an Offline Storage Files (.OST) and converted into new Personal Storage Files (.PST). This software works as all Microsoft exchange server versions like as 2010, 2007, 2003, 2000, 5.5 or 5.0 etc. Trail Edition of this software free to use and test the process after that you purchase it. After test user want to buy full version of this tool invest only $99.