How to Open OST File into Outlook - Version 3.0 How to Open OST into Outlook MS Exchange database are you encountering problems like it is showing error message such as breakdown of the exchange server, virus attack, server shutdown causing the file corruption etc? In that case your OST file has got corrupted. So you can use Open OST file and convert OST to PST. Outlook OST File free downloading is available at SysTools.After you satisfied you can invest in full licensed version of the software. The tool support about all Outlook version including 2000, 98, 2003, Vista and Win7, so you can easily Open OST File in 2003.You can online purchase of this software for full licensed version only at $99.