The only best solution in the world to open OST file without using Outlook is Enstella OST Converter software. It opens OST file in easy steps without using Outlook. The best thing about this software is that it is very easy to use for all users and gives great results to users. With this tool, you can open your OST file as well as convert it to different formats like PST, EML, MSG, ELMX and many others. Complete information on how to use it is available in the free demo version.

More info:- Easily open OST file without Outlook