How To Import OST File Into Office 365 in Easy Steps

Summary: Through this blog, we’ll learn the two best methods, manual and professional, that’ll help to import OST file into Office 365 account, and with this, we’ll know which way is the ideal solution to restore OST files in Outlook 365 quickly with the advanced features. Now let’s know about OST & MS Office 365. Download Now   Purchase Now

A Brief Introduction to OST Files & Office 365

OST: Outlook Data Files (.ost) are like special containers for your email and other information when you have an Exchange account or use the Cached Exchange Mode in Outlook. They let you work offline, meaning you can access your emails without an internet connection. These data files are also used for accounts that are set up using the Outlook Connector.

Office 365: Microsoft 365 is a group of useful computer programs and services created by Microsoft. It offers online services such as, OneDrive, and Microsoft Teams. It also includes programs like Word, Excel, PowerPoint, and Outlook, which you can use on computers, phones, and the Internet. Microsoft 365 is not just for individuals but also for businesses.

It has Exchange Server, SharePoint, and Yammer, which help companies collaborate and share information. You can get Microsoft 365 through subscription plans that give you access to these programs and services. These plans can include licenses for desktop and mobile software, as well as email and intranet services that are hosted for you.

Advantages of Using Office 365

  • This package contains Fancy Word, OneNote, Excel, and PowerPoint versions.
  • You get a whopping 1 TB of storage space on OneDrive’s cloud.
  • It allows sharing subscriptions with up to five people.
  • It comes with extra-strong security and lots of help if you need it.

02 Best Methods to Import OST File Into Office 365

We will discuss the two best manual and professional methods tested by experts. But the manual method is not a direct solution to open OST files In Office 365. We can upload OST files to Office 365 accounts separately.

Method 1: Perform OST to Office 365 Migration Using Outlook

The manual method is free and helpful for importing OST files to Office 365. This method is divided into two steps. Following these step-by-step instructions, you can easily upload OST to Office 365.

Step 1: Convert OST to PST File

There are two ways to convert OST files into PST. Both methods can export OST files to PST. The step-by-step guide is given below:

  • Convert OST Into PST Using Import/Export Feature
    • Firstly, log in to your MS Outlook account on your system.
    • Go to “File” in the menu bar.
    • Select the “Open & Export” option.
    • Click on “Import/Export” in the menu that appears.
    • Choose the option for exporting files to a file and click “Next.”
    • Select the “Outlook Data File (.pst)” option & hit “Next.”
    • Pick the specific folder you want to convert and click “Next.”
    • Then, press the “Browse” button and locate the File where you want to save the converted File.
    • At last, click on “Finish” to start the conversion process.
  • Export OST File to PST Using Archive Feature
    • First, click “File” at the top of the Outlook window.
    • Choose “Tools” from the drop-down menu.
    • Then, select “Clean up old items.”
    • Pick the folder that you want to archive.
    • Click “Browse” to choose where to save the archived File.
    • Finally, click “Finish” to finish the process.
    • You can choose any one technique to export OST to PST using Outlook.

Step 2: Import PST File in Outlook 365

This step is separated into two parts to import OST file Into Office 365. By following these guides, you can add PST files to Microsoft 365.

  • Configure Office 365 Account in Outlook
    • Open Outlook on your computer.
    • Click on “File” and select “Add Account.”
    • Enter your Office 365 email address.
    • Type in your Office 365 account password, confirm it, and click “Next.”
    • Ensure you’re also logged into your Office 365 account in your web browser.
  • Import PST File to Office 365
    • Again, open Outlook on your PC.
    • Go to File, choose Open & Export, and select Import/Export.
    • Choose Import from another program/file, click Next, Choose the Outlook data file (.pst) option, and click Next.
    • Click Browse to locate and add the PST file you want to import, then click Next.
    • Choose your Microsoft Office 365 account from the drop-down menu.
    • Click Finish to import your Outlook PST emails into your Office 365 account.

Note: The manual method is lengthy; you can import one File at a time: therefore: you should upload one OST file to Outlook 365, as it takes too much effort. The manual method is a technical way to upload an OST file to an Outlook 365 account, but by following the above step-by-step guide, you can easily import an OST File into an Office 365 account if you have technical expertise. This method is time-consuming and takes too much time to process. It can lose your data when you leave it out of any one step of this method. Most professional users avoid this method. I prefer you to import OST files Into Office 365 professionally without losing any data.

Method 2: Import OST to Office 365 Account Professionally

The OST to PST Converter is risk-free and secure software to import multiple OST files/folders to Office 365 at a time. It offers various features/filters that help make your tasks easy and short. It has a user-friendly interface; therefore, novice users can use it easily without difficulty.

Step-by-Step Instructions to Import OST Files into an Office 365 Account:

  1. Firstly, Download & Install OST to PST Converter on your system.
  2. Then, select the “Single File/Multiple Files or Select Folder” option and click Next.
  3. Choose the Select Files/ Select Folder Option.
  4. Now, choose OST files/folder and press the Open button.
  5. After selecting all the files, click on the Next button.
  6. Now, preview all selected files from the tree structure list.
  7. After that, select the files from the tree structure you want to migrate, and then click Next.
  8. Choose the Email Clients option, then select the Office 365 Option from the drop-down list.
  9. After all, enter the Email Address of your Office 365 account, then click on the Sing-In button.
  10. Last, choose the features/filters as per your requirements.
  11. At last, tap on the Convert button to start the process.

You can easily upload OST to Office 365 using the above instructions. It supports all Windows versions. It supports OST files created by Outlook 365/2019/2016/20110/2013, etc. You must download a trial version of the OST to PST Converter tool without cost; it can add 50 items per folder.


This article describes the best two methods to import OST files Into Office 365. Both ways are helpful and workable. But non-technical users may face some challenges while using manual methods, as the process has limitations. On the other hand, the professional approach is risk-free, and novice users can use this method without difficulty. Now it is in your hands to choose which way is perfect for your task.

Frequently Asked Questions

How to import an OST file into Thunderbird?

1. Install OST to PST Converter on PC.
2. Add OST file(s) by browsing.
3. Preview and select emails.
4. Choose the Thunderbird option.
5. Select MBOX format and features.
6. Set the file location to save the File.
7. At last, click on the Convert button to start the process.

How do I bulk import OST to Office 365 with attachments?

1. Download & run the OST to Office 365 Migrator on your system. 
2. Select files, browse, and add OST files.
3. Choose Office 365, and enter login details.
4. Use features like Remove Duplicate Items, Mail Filter, etc. 
5. Then, click Convert to migrate.

About The Author:

Related Post