How to Import OST File into Outlook 365? Easy Methods

Summary: Outlook OST files are offline copies of your mailbox that save emails, contacts, calendars, and attachments on your computer. The problem is that you cannot directly open these files in Outlook 365. This makes it difficult for users who want to access their data after being transferred to Microsoft 365. The good news is that there are safe ways to export this data. In this blog, we will study how to import OST file into Outlook 365 by using the manual methods and an automated OST to PST Converter Tool.

Common Scenarios Users Face While Migrate OST to Office 365

Many users struggle when transferring their OST files to Office 365 because the process is not simple. Here are some common situations where migration becomes necessary:

• When employees switch from an on-premises Exchange server to Office 365.
• If you delete the Outlook profile but keep the OST file on the system.
• When users need to access old emails, contacts, or attachments in Office 365.
• If a server crash or account deactivation damages the OST file.
• During company mergers or migrations, organizations upgrade email platforms to Office 365.
• When users want to backup OST data into Office 365 for security and compliance.

Real-World Example: A company shifted from Exchange 2013 to Microsoft 365 and found old OST files on local systems containing important emails. These OST files were not linked to the server, and manual methods didn’t work. The IT team used a professional OST migration tool, which safely imported all OST data into Office 365 without any data loss.

Multiple Ways to Import OST File into Outlook 365

There is no direct option to import OST files into Outlook 365, but you can convert your data using different methods. You can use manual steps like exporting OST to PST or use a professional tool that directly uploads OST data into Outlook 365. Let’s explore each method in detail:

Native Methods to Import OST File to Office 365

You can use manual methods to transfer data from an OST file into Outlook 365. These steps are free but take time and only work in certain cases. Also, they require Outlook to be properly configured with the original account. Let’s study native methods in detail:

Method 1: Import OST to Office 365 Using Outlook

This is the most common manual method and works only if your Outlook profile is active and the OST file is accessible. Follow the steps:

1. Firstly, start Microsoft Outlook with the connected account.
2. After that, go to File > Open & Export > Import/Export.
3. Further, select Export to a file and select Next.
4. To proceed, choose Outlook Data File (.pst) and select Next.
5. Meanwhile, select the folders you want to export.
6. Later, browse a location to save the PST file and select Finish.
7. Lastly, once the PST is created, import it into Outlook 365 using the same Import/Export option.

Method 2: Import OST File into Outlook 365 Using Outlook Archive

This method is useful for moving older or less frequently used mailbox items from OST into a PST file. Steps can be defined as:

1. Initially, start Outlook and go to File > Options.
2. Afterward, select Advanced.
3. To proceed, under AutoArchive, select AutoArchive Settings.
4. Further, select the folder, time range, and location to save the archive PST file.
5. Finally, after the archive process completes, import the PST into Outlook 365.

Method 3: Upload OST to Office 365 Using Drag and Drop

This method allows you to manually transfer selected items from OST to PST. Steps can be followed as:

1. At first, start Outlook with the configured OST account.
2. To proceed, create a new PST file: File > New Items > More Items > Outlook Data File.
3. Later, drag and drop emails, contacts, or folders from the OST mailbox into the new PST file.
4. At last, save the PST and then import it into Outlook 365.

Method 4: Import OST File into Outlook 365 Using Network Upload

This method is designed for IT administrators to upload and import PST files directly into Microsoft 365 mailboxes. The procedure can be followed as:

1. At first, sign in to the Microsoft 365 Admin Center.
2. Then, go to the Import Service option.
3. To proceed, use the Azure AzCopy tool to upload PST files to Microsoft’s cloud storage.
4. Further, create and upload a CSV mapping file to assign PST to user mailboxes.
5. Lastly, start the import job to move PST data into Office 365 mailboxes.

Drawbacks of the Manual Procedures

• Manual methods only work if the OST file is connected to an active Outlook profile.
• Outlook 365 does not support direct OST transfer, so users first convert OST to PST.
• The process is time-consuming when dealing with large mailboxes.
• There is a high risk of losing attachments, calendar entries, or other important data during transfer.
• Manual methods only import one file at a time and do not support batch migration.

Expert Solution to Import OST File into Outlook 365

Manual approaches fail when OST files are corrupted or inaccessible, which makes the process unreliable and time-consuming. In such cases, a professional OST to PST Converter tool proves to be the most effective solution. This tool is designed to handle all types of OST files, convert them into PST, and even import them directly into Outlook 365. It provides a secure, accurate, and hassle-free migration without risking any data.

Check this if you need to convert OST to CSV for data reporting, analyzing, or Excel purposes.

Follow the procedure to add OST file to Outlook 365:

1. At first, start the OST to Office 365 Migration Tool as an administrator.



2. Afterward, choose Select Files/Folder to add OST files, then select Next.


3. To proceed, review the selected file(s) in the preview panel and select Next.


4. Meanwhile, select Office 365 as the saving format and enter valid login credentials to sign in.


5. Later, apply advanced features and select Convert to start the process.

Note: If you do not want to directly convert to Office 365, you can also save it as a PST file.

Conclusion

Importing OST file into Outlook 365 can be done through several manual techniques. But these methods involve complex steps and are limited in handling large, corrupted files. For users who need a reliable and hassle-free migration, using a professional tool is the best approach. It provides data integrity, saves time, and provides advanced features to make the process smooth and efficient.

Frequently Asked Questions