Pats, I've been searching for a way how to open an ost file. I've been a problem with my .ost in MS Outlook. I can't get access to it from yesterday evening. I have many important messages in this file, unfortunately only two or three days and after I will get huge problems related to my job.
As there is a .ost file, that sounds very much like an Exchange email address - so you could have a Business Apps account with us rather than just a standard email. What errors do you get when you try to open the .ost file?