Migrating PST files to Office 365 (Microsoft 365) centralizes your email data on a single cloud platform. This allows you to securely access your mailbox from any device and helps to manage storage and data protection much better. To move PST files in bulk, you can use Microsoft’s native methods – Network Upload and Drive Shipping. To simplify the process and to migrate PST as well as OST files, you can use a specialized PST to Office 365 migration tool. In this article, we will explain these methods to bulk-migrate Outlook data files to Office 365.
How to Bulk Migrate PST Files to Office 365?
Following are the ways you can use to migrate PST files in bulk to Office 365.
1 – Network Upload
Network Upload is a native method provided by Microsoft to import multiple PST files into Microsoft 365 mailboxes at once. To start, you must create an Import Job via Purview portal within the Exchange Admin Center. You have to download the AzCopy tool to upload the PST files in a batch to a temporary Azure storage location in the cloud. Then, use the Microsoft 365 import service to import the PST files into the target users’ mailboxes. You also have to create a PST mapping file in CSV format, which is one of the most important steps of this method. It helps Microsoft 365 know which PST file belongs to which user mailbox. During the process, you can use filtering options to trim the import by item age or file type.
To import PST files in bulk via Network Upload, ensure the following:
- Assign the Mailbox Import Export and Mail Recipients roles to your admin account (preferably via a dedicated, low-privilege role group rather than using a Global Admin account).
- The size of the PST files is less than 20 GB as larger files can affect the import performance.
- PST files should not have more than 300 levels of nested folders.
- Any single import job targeting a user’s online archive does not exceed 100 GB of data.
- Ensure the PST files are available locally, on a network share, or ready for Azure upload.
- Verify the PST format. An ANSI PST belongs to Outlook 97–2002, while a Unicode PST belongs to Outlook 2003 and later.
Limitations of the Network Upload Method
You can use this method to import multiple PST files into Office 365 at once. However, it is a lengthy process and has some limitations, such as:
- Requires downloading AzCopy tool to upload the PST files.
- The size of the PST file should not be more than 20 GB.
- The mapping file should contain a maximum of 500 rows, otherwise validation will fail. Therefore, you need to create multiple mapping files.
- Performing multiple manual steps is slightly complicated for a non-technical person.
2 – Drive Shipping
Drive Shipping is another native option for bulk importing PST files into Microsoft 365. In this, instead of uploading the PST files to Azure storage, you have to copy your files onto a BitLocker-encrypted external hard drive and physically ship it to a Microsoft data center. Once received, the data center personnel upload the PST files to a temporary Azure storage area. After this, you can complete PST import process using the steps same as the Network Upload method: submitting a CSV mapping file, applying data filters, and starting the import job.
Before importing PST files using the Drive Shipping method you should know the following points:
- It is not a free method to import multiple PST files. 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.
- Make sure you encrypt the hard drive using BitLocker via WAImportExport.exe tool. The tool also generates the encrypted key. You must safely store the keys in a password protected document, or in an encrypted USB drive so Microsoft personnel can access the drive while uploading your PST files on the cloud.
- Ensure that the hard drive you’re sending contain the data according to applicable laws. You can take the help of the legal advisors to verify the drive before shipping.
- Use only NTFS-formatted 2.5-inch SSDs or SATA internal hard drives up to 10 TB with standard adapters. According to Microsoft, you should avoid built-in retail external USB drives.
Limitations of Drive Shipping Method
Although this method helps you import the PST files into Office 365 in bulk, it has a few limitations, such as:
- It is time-consuming and tedious process as you have to follow multiple steps.
- It can take several days to upload PST files on Azure storage.
- It is costly as Microsoft charges $2/GB or $2000/TB of data for uploading PST files to Azure Storage.
Use Specialized PST to Office 365 Migration Tool: The Easiest Way to Bulk Import PST/OST
For a quick, hassle-free process, you can use a specialized PST to Office 365 migration tool, such as Stellar Migrator for Outlook to import multiple PST/OST files into Office 365 with complete integrity. You can use it to import files in bulk directly into Microsoft 365. It only requires a CSV file with mapped source and target mailboxes.
The tool directly migrates files with complete accuracy from local drives, shared folders, or network paths. It is a pay-per-use software, which means you have to only pay for the number of mailboxes or data files you migrate.
Key Features:
- It allows you to import files in bulk directly into Microsoft 365 or a live Exchange Server from local drives, shared folders, or network paths without gathering them in one place.
- It simplifies the process by eliminating the need to run complex PowerShell scripts or download and use AZCopy tool.
- It allows you connects directly using Auto Registration or Manual Registration options. It eliminates the need to assign mailbox roles, upload mapping files, or ship hard drives to Microsoft.
- It auto-maps mailboxes from the source (OST/PST) to the target (Microsoft 365) and imports data without size restrictions while maintaining complete integrity.
- It provides incremental/delta migration, shows real-time migration progress, and allows you to resume a failed job right where it stopped.
To use Stellar Migrator for Outlook, make sure:
- You have ready mailboxes (the target Office 365 or Exchange mailboxes).
- You have a Global Admin account to link the tool to your Office 365 system.
- A mapped CSV file.
Watch this video to learn how to use the tool to import bulk Outlook PST into Office 365.
When to use PST to Office 365 migration tool to import Bulk PST to Office 365
You can use the software to import PST files when:
- You want to directly import PST into Office 365.
- You need to migrate PST files from a single or multiple devices to Office 365.
- You need direct mapping and want auto source and target mailbox mapping.
- You want to edit the mapping file. For example you want to define a custom folder on the mapping file.
- You want to easily import encrypted OST/PST files into Office 365.
- When you want to export OST/PST to live Exchange Server.
Limitations
- It is a pay-per-use software, so setting it up incorrectly will waste your paid credits.
- The software cannot create new Microsoft 365 accounts; all target mailboxes must be set up in advance.
- Connection credentials are not stored and must be re-entered manually for each new migration job.
Conclusion
Microsoft 365 provides enhanced data security safeguards, along with various inbuilt tools and services. This article discusses easy ways to migrate bulk PST/OST files to Office 365. You can use native Microsoft methods, such as Network Upload and Drive Shipping. However, these methods are time-consuming as they require multiple steps and do not support migrating OST files. To migrate PST and OST files in bulk, you can use Stellar Migrator for Outlook – a professional PST to Office 365 migration tool. It allows you to directly migrate Outlook data files from your system to Office 365 without any hassle.