Importing PST Files into Office 365 in Bulk: Simplified Guide

If you are an IT admin and want to bulk import PST files into Office 365 (Microsoft 365), the available methods that you can use are Network Upload and Drive Shipping.

But these manual methods are time-consuming, lengthy, and may require additional resources. There is, however, another way to bulk import PST files into Office 365 – a third-party PST to Office 365 migration tool. In this guide, we will be looking at these methods in detail. 

What is the Need to Bulk Import PST Files into Office 365?

Listed below are some reasons to import PST files into Office 365: 

• You can create an online repository of PST files on a single platform.

• Users can remotely access their mailbox data stored on the cloud from anywhere and using any device.

• PST files stored on local machines are prone to corruption. Importing them into the Microsoft 365 can prevent data corruption.

• Office 365 provides enhanced security features, like advanced threat protection, anti-phishing, anti-spam, and anti-malware protection, identity security capabilities, and much more.

How to Bulk Import PST Files into Office 365?

Mentioned below are some methods to import PST files into Microsoft 365 in bulk.  

Method 1: Use Network Upload

You can use the Network Upload method to bulk import PST into Office 365. In this, you have to create an “Import Job” via Microsoft Purview in Microsoft Exchange Admin Center (EAC). Then, download the Azure AzCopy tool and use the SAS URL to upload PST files from your device to the Azure Storage. Once the files are uploaded on the cloud storage, you can easily import them into Microsoft 365. 

Note – Before you proceed, ensure that the size of the PST files is less than 20 GB. Larger files can affect the PST import performance. 

Here are the steps you have to follow: 

• Copy the SAS URL and download AzCopy

• Upload your PST files to Azure Storage

• Create the PST Import mapping file (CSV file)

• Create a PST Import job

• Filter data and start the PST Import job

Method 2: Drive Shipping

Another native method to bulk import PST files into Microsoft 365 is Drive Shipping. In this, you have to ship a BitLocker-encrypted external hard disk drive containing all the PST files to Microsoft data center. The Microsoft professionals will then upload the PST files to the provided Azure cloud storage. After this, the PST import procedure is similar to the Network Upload method. 

Some points to keep in mind: 

• Microsoft charges $2/GB or $2000/TB of data.

• Ensure that each PST file you add to the HDD is not more than 20 GB in size.

An Easy Way to Import PST Files into Office 365 in Bulk 

You can use Stellar Migrator for Outlook – a powerful PST to Office 365 migration tool to effortlessly import PST into Office 365. This tool allows you to migrate PST files from a single or multiple systems to Office 365 with complete accuracy. 

With this tool, you can simplify the process of importing PST files (mailboxes) in bulk into Microsoft 365 by using a CSV file with names of already mapped source and target mailboxes.  

This tool makes the PST Office 365 import process fast and effortless as you can directly connect to the tenant using Auto Registration or Manual Registration option. For Auto Registration, you just need to enter the Microsoft Azure (Entra ID) credentials. 

For Manual Registration, you have to manually enter details, such as Email Address, Application (Client) ID, Directory (Tenant) ID, and Client Secret Value. This PST to Office 365 migration tool auto-maps the mailboxes from the source (OST/PST) to the target (Microsoft 365). 

Here is what this software offers: 

• Directly import PST into Office 365

• Migrate PST files from a single or multiple devices to Office 365

• Auto source and target mailbox mapping

• Easily import encrypted OST/PST files into Office 365

• Facilitates export of OST/PST to live Exchange Server

• Auto-split large-sized PST files

• Incremental migration to prevent data duplication

Now, let’s see the step-by-step process to migrate PST files to Office 365 in bulk using this powerful PST to Office 365 migration software: 

• Download and install the Stellar Migrator for Outlook software on your Windows PC.

• Launch the software.

• You will see the Create migration job window. Enter the Job name and choose the Multiple Mailboxes option. Click Next.

Note: You can also use the Migrate mailboxes using CSV option if you have created a .csv file containing the details of all the source and target mailboxes. 

• The Select source window will appear. Click on Select Files to choose the PST files you want to migrate.

• Click on the Next button.

• The Select target screen will show up. Choose the Microsoft 365 option and click Next.

• Now, the Connect Target window will appear. Choose either Auto Registration or Manual Registration.

• Auto Registration – It allows you to automatically connect to Microsoft 365 by using an individual Microsoft 365 account credentials or Microsoft 365 Global Admin account credentials.

• Manual Registration – It requires you to enter the details, such as Email Address, Application (Client) ID, Directory (Tenant) ID, and Client Secret Value. Click on Validate after that.

• After the software successfully connects with O365, it will display a list of Target mailboxes that are found on Office 365 (target server). Here, you can preview and validate the mailboxes. Then, click Next.

Note: If you have more number of target mailboxes than the displayed ones, use the Load mailboxes using CSV option to list all the target mailboxes. 

• Next, you’ll see the Map mailboxes screen. Here, the software will display source and target mailboxes. You can change the mailboxes mapping from the Edit column (Pencil icon). If you want to migrate PST file data to a specific folder, use the Click to specify option. Click on Next after finalizing the mapping.

• The Date filter screen will appear. Choose a date filter option and click on Next.

• Now, you’ll see the Folder type window. Select the folders you want to migrate. By default, all mailbox folders are selected. Click on Next.

• On the next screen, you’ll see Max concurrency. This defines how many PST files can the tool migrate at the same time. Use the dropdown list to select the number of mailboxes to be migrated simultaneously. You can select a maximum of 10 mailboxes. Click on Next.

• Finally, the Summary window will appear. Review all the selected parameters before creating the job.

• After you have reviewed the selections, click on Finish.

• You will see the Job created dialog box along with the Job listed. Click OK.

Now, click on Start in the ribbon to initiate the migration process. 

• Next, click on Connect to log in to the licensing server.

• After the connection is established, the software will begin the migration.

Once the migration is started, you can also track the progress of mailbox migration. After the migration job is completed, you will see the Completed status in the Mailbox progress window. 

Bottom Line

Cloud platforms such as M365 are quite popular for varied reasons. They make the mailbox data available at all times, simplify data management, and provide enhanced data security safeguards. For importing PST files into Office 365, you can use native methods – Network Upload and Drive Shipping.

But these methods are tedious and time-consuming. A simple way to efficiently import PST into Office 365 is by using Stellar Migrator for Outlook – a third-party PST migration tool that lets you migrate PST files into the Office 365 without any hassle.