Unable to open ost file outlook - Version 3.3 If Outlook user Unable to open OST file then use OST Recovery tool to able open OST file as PST file and easily open Offline Storage Files (.OST) in MS Outlook. OST Recovery tool repairs corrupt OST file as well as convert OST file to PST, EML and MSG file format. OST file is important for Outlook user because when email is lost due to any reason that time you restore from OST file by OST Recovery tool. OST Recovery software repairs OST file error after that convert OST file to PST file easily and supports all Microsoft Exchange Server 2010, 2007, 2003, 2000, 5.5 , 5.0 and supports all versions of Windows OS like 97, 98, 2000, XP, 2003, 2007 and 2010. User can try this software with Demo Version free of cost, after evolution you want to purchase full version then pay only $99. For download and get more info visit-: http://www.convertostpst.org