OST files store important piece of information of Outlook mailbox and also used by Exchange Server to perform smooth synchronization between the two applications. Kernel for OST to PST tool is a third-party OST file recovery software that also performs smooth conversion OST files to PST files. This tool is compatible with all versions of MS Outlook (2013), Outlook Express (6.0), Exchange Server (2013) & Windows OS (8.1 & windows server 2012).