Which EML Import Method Fits You?
An EML file is one email saved on disk. To import EML to Microsoft 365, you move the files through Outlook, a PST file or a migrator, since Microsoft 365 has no upload page for them.
| Method | Needs admin | Use case |
|---|---|---|
| Drag into Outlook | No | A few files for one mailbox |
| PST network upload | Yes | Bulk import for many mailboxes |
| Migrator | Admin access to accounts | Direct import to many accounts |
Can You Drag EML Files Into Outlook?
Method #1: Drag and Drop (Free)
Who it suits. Anyone with a few files. Extra application. Outlook connected to Microsoft 365.
- Open Outlook with your Microsoft 365 mailbox to import EML mail.
- Create a folder for the imported mail.
- Open the Windows folder that holds the files.
- Select the files and drag them into the Outlook folder.
- Wait until the items show in the folder and check the dates.
Move the files in small batches. A large drag can stall Outlook.
What is the PST Network Upload Method?
Method #2: PST Network Upload (Free for Admins)
Who it suits. Admins with many mailboxes. Extra application. Outlook and AzCopy.
- Import EML mail into an Outlook data file and export that folder to a PST file.
- Sign in to the Microsoft Purview portal as an admin and open the Import page.
- Create the import in Purview and copy the SAS URL.
- Upload the PST files with the AzCopy tool.
- Build the CSV mapping file that links every PST file to a mailbox.
- Start the import and filter the data if you need to.
Microsoft states that AzCopy is the only supported upload method, that PST files should remain below 20 GB and need unique names.
Microsoft adds that your account needs the Mailbox Import Export role in Exchange Online.
Can a Migrator Import Directly to Microsoft 365?
Method #3: Migrator Software (Paid After Demo)
Who it suits. Admins and users with large folders. Extra application. EML to Office 365 Migrator.
EML to Office 365 Migrator imports EML files to Microsoft 365 for up to 10 accounts at once. The vendor page lists folder structure preservation, a date filter, delta migration and CSV mapping.
- Start the software and select Add Files or Add Folder.
- Preview the EML items.
- Sign in to the Microsoft 365 destination.
- Map the source folders to the user accounts.
- Set the filters and select Start.
The free version imports to 2 user accounts.
What should You Check After the Import?
- Compare the item count in the folder with the number of EML files.
- Open five items and check the dates, senders and attachments.
- Retain the source files until the check ends.
- Plan for the import service limits when you upload large PST files.
Need a Windows only route? Read how to import EML to Outlook.
Frequently Asked Questions
Can You Import EML Files to Microsoft 365 Directly?
Microsoft 365 has no upload page for EML. Use Outlook, a PST file or an EML migrator.
What is the First Step With a Few Files?
Open Outlook, create a folder and drag the EML files into it.
Which Tool does Microsoft Support for PST Upload?
Microsoft states that AzCopy is the only supported method for the network upload.
What Size Limit Applies to PST Files in the Upload?
Microsoft states that PST files should be no larger than 20 GB and need unique names.
Which Role does the PST Import Need?
Your account needs the Mailbox Import Export role in Exchange Online.
How Many Accounts can EML to Office 365 Migrator Import to?
The vendor page lists up to 10 accounts at once. The free version imports to 2 user accounts.
Does the Drag Method Preserve Folders When You Import EML?
No. You create the Outlook folder yourself, so use the migrator when you need the source folder structure.
Author's Verdict
Use drag and drop to import EML files in small numbers.
Use PST network upload or a migrator to import EML files in bulk.
Key Takeaways
- You import EML through Outlook, PST or a migrator.
- AzCopy is the supported PST upload tool.
- EML Migrator imports to 10 accounts at once.
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