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Storing Exchange mailbox data on a cloud-based platform like Microsoft Office 365 provides several important benefits for users and organizations. With cloud storage, emails and other mailbox items can be accessed from almost any location, as long as there is a stable internet connection. This level of accessibility and convenience encourages many Exchange users to move their offline Outlook data to the cloud for better availability and improved data protection.

An OST file in Microsoft Outlook stores a synchronized local copy of an Exchange mailbox that allows users to work even when they are not connected to the internet. However, if users want to make this mailbox data accessible through Office 365, the OST file must be migrated to the cloud environment. There are multiple ways to complete this process, and the best method often depends on the user’s technical knowledge as well as the amount of data that needs to be transferred.

Reasons Users Need to Open OST Files in Office 365

There are several situations where users need to migrate data from an OST file to Microsoft Office 365. Moving mailbox data to the cloud can improve accessibility, security, and reliability. Below are some common reasons why users choose to perform this migration:

• Adopting Cloud-Based Services: Many organizations shift to Office 365 to benefit from its cloud-based environment, which offers easier access, collaboration tools, and improved data management.
• Recovering Data After Server Issues: If the Exchange server becomes damaged, crashes, or experiences corruption, users may need to extract important mailbox data from the OST file and move it to Office 365 to restore access.
• Minimizing Dependence on Exchange Servers: Maintaining an Exchange server can require regular updates, monitoring, and downtime for maintenance. Migrating data to Office 365 helps reduce this dependency and simplifies email management.
• Restoring Data After Accidental Deletion: In cases where mailbox items are mistakenly deleted, transferring data from the OST file to Office 365 can help users recover and securely store important emails and information.

Methods to Open Outlook OST Files in Office 365

At present, Microsoft does not offer a direct feature to upload an OST file straight into Microsoft Office 365. However, users can still move their mailbox data to the cloud by using alternative approaches. Below are two commonly used methods for completing this task.

Method 1: Convert OST to PST and Import Manually

In this method, the OST file is first converted or exported into a PST file format using Microsoft Outlook. Once the PST file is created, it can be imported into an Office 365 mailbox using Microsoft’s available import options. Although this method works effectively, it may take more time and often requires a certain level of technical understanding to complete the process correctly.

Method 2: Use an Automated OST to Office 365 Tool

Another option is to use a professional third-party OST Converter tool designed to transfer OST data directly to an Office 365 account. These tools are built to simplify the migration process by minimizing manual steps and reducing the chances of data loss. They also help preserve the original folder structure and ensure that emails and other mailbox items remain intact during the transfer.

Manual Method to Save an Outlook Offline OST File in Office 365

The manual technique for opening an OST file in Microsoft Office 365 involves an indirect procedure. Because OST files cannot be uploaded directly to Office 365, they must first be converted into a compatible format before the data can be transferred to the cloud.

In this process, the OST file is initially converted into a PST file using Microsoft Outlook. After the PST file is created, it can then be imported into the Office 365 mailbox using the available import options provided within the platform.

Overall, the manual method includes two primary steps: first, converting the OST file into PST format and then uploading or importing that PST file into the Office 365 environment.

Step 1: Convert OST Data into PST Format

There are several built-in options in Microsoft Outlook that allow users to export mailbox data from an OST file into a PST file. Below are some commonly used methods to perform this conversion.

Method 1: Create a New PST File and Move Mailbox Data

This method involves manually transferring mailbox content into a newly created PST file.

• Open Microsoft Outlook on your computer.
• Create a new PST data file within Outlook.
• Navigate to the folders stored in the OST mailbox.
• Select the required emails or folders and copy them into the newly created PST file.

Method 2: Use Outlook’s Archive Option

Outlook also includes an archive feature that allows users to save mailbox items locally in a PST file.

• Launch Outlook and go to File > Cleanup Tools > Archive.
• Select the folders you want to archive.
• Choose the destination where the archive PST file will be saved and start the process.

Note: This approach does not export Outlook contacts.

Method 3: Export OST Data Using the Outlook Export Wizard

Another way to create a PST file is by using the built-in export tool in Outlook.

• Open Outlook and navigate to File > Open & Export > Import/Export.
• Choose Export to a file and proceed to the next step.
• Select Outlook Data File (.pst) as the export format.
• Pick the mailbox folders you want to export, select a location to save the file, and finish the export process.

Note: This option works only when Outlook is connected to an active Exchange account.

Step 2: Upload the PST File to Office 365

After converting the OST data into PST format, the next step is to upload the PST file to Microsoft Office 365. Microsoft provides two different methods for importing PST data into the cloud.

Method 1: Network Upload Using Azure AzCopy

This method transfers PST files to Office 365 through Microsoft Azure AzCopy.

• Install the Azure AzCopy utility on your system.
• Use the Shared Access Signature (SAS) URL provided by Office 365 to authenticate the upload.
• Create a PST mapping CSV file that defines how the data will be imported.
• Configure an import job in the Office 365 Security & Compliance Center.
• Begin the upload and track the progress of the import process.

Method 2: Drive Shipping to Office 365

Drive shipping is another option, especially useful when dealing with large PST files.

• Copy the PST files to a physical hard drive.
• Send the drive to Microsoft following their official guidelines.
• Microsoft will upload the data directly to your Office 365 tenant once the drive is received.

OST to Office 365 Converter – An Automated Way to Export Outlook Offline OST File to Office 365

Moving Outlook OST files to Microsoft Office 365 can be difficult, particularly for users who do not have advanced technical knowledge. The manual process usually involves several stages and can become even more complicated when the OST file is large, damaged, or inaccessible. For this reason, many users prefer using professional third-party tools to simplify the migration process.

An automated OST to Office 365 Converter provides a convenient and efficient solution for transferring Outlook offline data directly to an Office 365 account. The software allows users to move mailbox items from OST files to the cloud with minimal effort while maintaining data accuracy. Its easy-to-navigate interface makes it suitable for both IT administrators and users with limited technical experience.

The tool is compatible with most Windows versions, including Windows 10, and supports both individual and bulk OST migrations. This means users can migrate a single mailbox or multiple OST files in one process without complications. Additionally, the software offers a free trial edition that lets users export up to 25 items from each folder to Office 365, allowing them to test its features and performance before upgrading to the full version.

Conclusion

In this guide, we explored different ways to open Outlook offline OST file data in Microsoft Office 365. The choice of method largely depends on the size of the data and the user’s level of technical expertise. Manual techniques can work well when dealing with a limited number of OST files, but they often involve several steps and may require a good understanding of the process.

For organizations or users handling large amounts of mailbox data, using an automated OST to Office 365 Converter can be a more practical option. Such tools simplify the migration process, reduce manual effort, and help ensure that emails and other mailbox items are transferred accurately and securely.