2 Different Methods to Import OST to Office 365

Summary:- Import OST to Office 365 in the easiest way possible manually using this guide. We are going to explain the several methods for migrating the OST files into Outlook 365. Firstly, save OST files as PST and import them to Microsoft Office 365. You can also opt for a professional OST to PST Converter solution to import OST files into Office 365 directly.


MS Outlook is a prominent email client that provides a lot of features and functions. It maintains a steady flow of sending and receiving email messages. However, often users complain about the storage space that keeps getting full. Sometimes OST files get corrupted and data is either lost or inaccessible. As a result, many users import OST to Office 365 to secure their data and to have a backup of their Outlook data in other locations. To protect it from problems like inaccessibility and even worse permanent data loss.

Well, there are many other reasons why users import Outlook OST to Office 365. Because users face different problems in maintaining OST files, some of which are mentioned below.

Significant Reasons to Import OST to Office 365

If you are wondering why users move OST files to Office 365 then read below to explore some prime reasons that cause the migration of Outlook OST to Office 365.

  • The storage space of Office 365 is greater than OST files. So it is more efficient in storing the data on a large platform.
  • Sometimes OST files become inaccessible and cause problems; on the other hand, Office 365 provides accessibility of data from anywhere.
  • You can import OST files into Outlook 365 to access them on multiple devices.
  • Office 365 provides a reliable platform that is secure from file corruption which makes users shift from OST to Office 365.

These are a few dominating reasons that cause Outlook migration to Office 365. Let’s move ahead to the solution part that will assist you in exporting your OST files to Office 365.

How Can I Import OST Files to MS Outlook 365?

You cannot import OST to Office 365 directly with the assistance of manual methods. For that, first, you need to export the OST files in the Personal Storage Table(.pst). And then secondly import the exported PST file into Office 365. It’s an easy procedure that consists of two major steps that you are required to follow.

Method 1: Save OST as PST and Import it Into Office 365 Manually

  • Save OST Files in PST Format
  • Import the PST file into Office 365

Step 1: Use Outlook Import/Export Options to Save the OST file to PST

MS Outlook provides a built-in feature to save the OST files as PST with the assistance of the Import/Export option.

  1. Open MS Outlook> and go to File >> Open & Export >> Import/Export>.
  2. Choose Export to a file> and press Next>.
  3. Select Outlook Data File(.pst)> and hit the Next> button.
  4. Pick the folder you want to export and click Next>.
  5. Browse> your resultant file to its saving location.
  6. Click Finish> to complete the process.

Note: Password protects your PST file to protect it from unauthorized access, otherwise click Cancel.

By following the above instructions you can export OST to PST. Now, let’s move ahead to the next step. Here, there are two ways to import the PST file into Office 365.

Step 2: Import the PST file into Office 365

There are two methods to import PST files into Office 365 manually. In this section, we are going to explain all two methods so that you can import your PST data into Office 365.

  • Use Azure AzCopy
  • Use Drive Shipping to Microsoft

1. Using Azure AzCopy to Import into Office 365

  1. Download Azure AzCopy, Install it, and then copy the Shared Access Signature(SAS) URL. (It will allow the necessary permits to import the PST files into Azure.)
  2. Transfer the PST to Office 365 and create a PST to map(.csv).
  3. Now, create an import job in Outlook 365 on purpose to add PST.
  4. Finally, set a data filter and initiate the PST importing procedure in Office 365.

Note: This method is facilitated by the cloud program of Microsoft which is separate from Office 365. That’s why you need to implement some precautions before starting this procedure.

  • You need to have the assigned Mailbox Import Export Role by the Office 365 Administrator to implement the process. These types of Roles can only be assigned by the Administrator or the Organization Management Role group because it is disabled by default and the user or group cannot access it.
  • This method will only work with the AzCopy tool. Because you can’t directly use the Azure Storage Explorer to transfer the PST file.
  • To access the folder the PST file needs to be in the network–shared folder or else it will fetch the folder.
  • This process is not valid for files larger than 20 GB.
  • The retention hold policies of Office 365 will remove very old incoming emails. So, after importing the PST files, change the retention policies of Office 365 if your emails are quite old.
  • Lastly, it can’t upload messages larger than 35 MB to Office 365.

2. Use Drive Shipping to Import PST to Outlook 365

Through Drive Shipping, you can copy the data of the PST files to a hard drive and transfer it into the drive of Microsoft. Here, Microsoft copies the data from the hard drive and sends it to your Office 365 mailbox.

After following the above steps you can import the PST file into Office 365. However, there is another approach that can import OST to Office 365 directly using an automated solution.

Method 2: Import the OST File into Office 365 using a Professional Tool

OST Converter Tool is an optimum solution to import OST files directly to Office 365. You will just have to add the OST file to the tool and import it directly to your Office 365 account. For a better understanding, you can check the OST to O365 migration process below.

Steps to Import OST File to Microsoft Office 365

  1. Download and Install the OST converter on your system.
  2. Select the folder that you want to Import and press Next.
  3. Choose Office 365 from the software drop-down list.
  4. Enter your Office 365 username and password and log in.
  5. Click Convert to start the importing OST file process.

By following the above instructions you can import OST file data directly to Office 365 with ease and security.


In this context, we have discussed how you can open an OST file in Outlook 365 and its various methods. Well, there is a manual method that has quite a lengthy process and is complicated but if you want to choose then, it’s up to you. However, professionals always recommend the automated solution, because of the inconsistency and failure of the manual methods. In addition to this, the automated solution imports OST to Office 365 in bulk.

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About The Author:

Roshan Fatima is a Technical Writer at Data Conversion Tools. She is a Tech enthusiast, holding over 2 years of experience in Data Recovery Solutions. She loves researching and providing solutions to technical problems and tips and tricks to solve Windows technical issues. In her free time, she likes to read books and novels. Enjoys traveling and exploring new things.

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