Today I suggest you choose SysInspire OST to PST converter Software. This is the best tool for import an OST File into Office 365, it has a best GUI( graphic user interface) it can help people to use OST to PST converter Software, It can convert you OST file in to Multi formats Such as EML, EMLX, Office 365, IMAP, HTML and 10+ More formats are available. It has one more great feature is the Split option where you can split your PST in small PST files.