I would recommend OST to PST Converter tool to perform OST to Office 365 migration. This is a very advanced tool and provides you many advanced features. By using this tool, you can convert OST to PST, Zimbra, Gmail, EML, EMLX, vCard, ICS, MSG, Office 365, Live Exchange server, MBOX and etc. The software is compatible with Windows OS and supports all versions of MS Outlook, including Outlook 2019. This conversion helps you in quick and easy migration of OST email database to MS Outlook with all messages, contact lists, calendar entries, to-do-lists, etc.
You can convert OST to PST file format. Then you can try Mailvita OST to PST Converter tool for Mac. The Mac user can take the help of the OST to PST Migration on Mac for a safe and secure conversion. It also increases Offline OST file data along with whole corrupted Outlook OST email items such as - Inbox, outbox, sent mail, note, task, journals, and draft, etc. This software is easy to handle by all technical and non-technical users without any acknowledged help. It also works on all MS Outlook versions like 2010, 2013, 2016, and 2019. This software supports all Mac OS versions.
I recommend to use DataVare OST to PST Converter app to recover and Migrate Offline OST files into Outlook PST file format with 100% data accuracy. The tool is available with free demo edition to give complete satisfaction for all users before purchase the license version. It is a standalone application that doesn’t required any third party application to complete the process so go with this utility to solve out OST to PST migration related issues.