Choose OST to Office 365 Converter
from KDETools software is a trusted solution to convert OST to Office 365 mailbox with ease. This ost to office 365 converter tool is the easily Migrate offline ost files items like contacts, emails, tasks, and calendar to Exchange account faster. This ost to office 365 migration utility supports all the version of MS Outlook and Windows OS. So if you are in serious problem then you should try at least once.
Convert OST to Office 365