If you want to recover deleted OST files so, here I suggest you get SysInspire OST to PST converter tool. This tool can convert OST files into multiple file formats such as PST, EML, EMLX, Office 365, Yahoo Mail, Gmail, MSG, etc. It has a demo version allowing users to convert 25 items from each folder. It supports all versions of Windows OS. This tool does not require the installation of MS Outlook on users' PCs to open the OST file. It has an email filtration option users can convert emails by using specific dates. It has technical support all users can get help by email or live chat.