Office 365 (Microsoft 365) – a cloud-based subscription service –provides various productivity tools, including Outlook for email communication, Microsoft Teams for collaboration, and others. It offers flexibility of accessing data from anywhere, at any time, and using any device. To be at an advantage, businesses and organizations prefer this cloud-based service over desktop-based email clients, like Mozilla Thunderbird.
However, migrating from Thunderbird to Office 365 is easier said than done. It isn’t a simple task as both the platforms use different file formats – Thunderbird uses MBOX file (.mbox) format, whereas Office 365 (Microsoft 365) supports the proprietary PST file (.pst) format.
But there are various specialized MBOX to PST converter tools available that can help to migrate Thunderbird data (MBOX file) to Office 365.
This post will explore the detailed process of migrating mailbox items from Thunderbird MBOX file to Office 365 using a powerful MBOX to PST converter tool. Additionally, there is a stepwise workaround mentioned ahead to migrate mail items from Thunderbird to Office 365.
Why Migrate from Thunderbird to Office 365?
Enterprises migrate from Thunderbird to Office 365 (M365) to leverage several advantages of the cloud-based platform, which Thunderbird – a desktop-based client – doesn’t provide. Making the switch has its own advantages such as:
- Anytime access of emails, contacts, etc., from any part of the world and using any device
- For productivity applications, such as Microsoft Teams, SharePoint, OneDrive, Word, etc.
- To easily manage user accounts, policies, and permissions via M365 Admin center, which is not possible with Thunderbird
- Keep the infrastructure compliant with eDiscovery, litigation hold, and audit logging
- To protect user privacy and data with enterprise-grade security checks, like Multi-Factor Authentication (MFA), Advanced Threat Protection, etc.
Key Differences between Mozilla Thunderbird and Office 365 (Microsoft 365)
Here are some key differences between Mozilla Thunderbird and Office 365.
| Mozilla Thunderbird | Office 365 (Microsoft 365) |
| Free desktop-based email client | Cloud-based subscription service |
| Supports MBOX file format | Supports PST file format |
| Suitable for email communication | Cloud-based enterprise solution that provides access to a suite of productivity tools |
| Requires additional plugins (add-ons) to export/import data | Built-in features to import/export data |
| Installed as a desktop application on Windows, Mac, and Linux systems | Cloud-based service accessibleasvia desktop and mobile application on various platforms |
| No dedicated customer support is available | Dedicated customer support is available |
| No native calendar sync with Exchange or Microsoft 365 (add-on required) | Full native calendar integration with Exchange Online and Outlook |
| No built-in mailbox migration tools | Microsoft 365 admin center includes built-in mailbox migration tools |
Before you Migrate (Pre-Migration Checklist)
Here’s you should do prior to migrating your Thunderbird data to the cloud platform:
- Back up profile folder of Thunderbird to an external drive
- Export mailbox data to a .mbox file
- Install and configure Outlook desktop with your Office 365 account
- Verify your Office 365 mailbox storage quota, if you’re importing large file
Simplest Way to Migrate Thunderbird Data to Office 365
An easy way to migrate Thunderbird data to an Office 365 account is by using Stellar Converter for MBOX Technician – an advanced MBOX to PST converter tool that effortlessly migrates Thunderbird MBOX file data, including emails, contacts, calendars, etc., to an Office 365 account with 100% accuracy and complete data integrity. It uses Microsoft’s Modern Authentication technique to securely connect and export the MBOX file data to mailboxes on Office 365 (Microsoft 365).
Some more highlights of this tool:
- Convert and save the mailbox data as PST, PDF, RTF, EML, etc.
- Multiple email clients supported, Apple Mail, Eudora, Entourage, Netscape, SeaMonkey, Spicebird, and more
Now, let’s see how to use this tool to migrate Thunderbird MBOX data to Office 365:
- Download Stellar Converter for MBOX Technician from its official page.
- Install it.
- When you launch the tool, you will see the Select MBOX window. Use the dropdown menu against the Select Mail Client option to select the email client (Thunderbird).
- Once you select the Thunderbird email client, the tool will automatically select the default path of the Thunderbird MBOX file.
Note: If you want to selectMBOX file stored at a different location, click on the Select Identity button.
- After selecting the MBOX file, click on Convert.
- The tool will scan the MBOX file and display all the mailbox items.
- You can preview the mailbox items.
- Choose the Export to Microsoft 365 option in the Save As window. Click Next.
- Choose the Export to Microsoft 365 option in the Save As window. Click Next.
- The Microsoft 365 Login window will show up.
- Choose the destination M365 user profile from the dropdown list and click Migrate.
Note: The tool auto detects the M365 profile configured with the Outlook application.
- At the end, you will see the “Migration Successful” dialog box. Click OK to complete the operation.
Manual Method to Migrate Thunderbird Data to Office 365
There is a way to migrate Thunderbird to Office 365. In this, you will configure the O365 account in Thunderbird, and then drag and drop the Thunderbird email messages into it. Here’s how to do this –
- Launch Thunderbird
- Click on the gear icon at the bottom-left corner to open Settings.
- Click on Account Settings.
- Then, click on Account Actions in the left pane and select the Add Mail Account option.
- On the Account Setup screen, enter your Microsoft 365 credentials and click on Configure Manually.
- Next, add the following details:
- Incoming: IMAP|outlook.office365.com|993|SSL/TLS|OAuth2
- Outgoing: SMTP|smtp.office365.com|587|STARTTLS|OAuth2
- Click Re-test to test the settings. Once it is successful, click on Done.
Wait for the completion of synchronization.Then, drag and drop the required emails from your Thunderbird into Office 365.
Limitations of the Above Workaround
The above workaround can work but it has some limitations, such as:
- Suitable for migrating only emails
- lengthy and time-consuming process
- Incorrect configurations settings may prevent Thunderbird from establishing connection with O365
Common Thunderbird to Office 365 Migration Issues
Here are some problems that occur while migrating mailbox data from Thunderbird to Office 365 –
- IMAP method is very slow or times out in case of large mailboxes
- ImportExportTools NG tool fails to work while exporting MBOX file due to conflicting add-ons in Thunderbird or version incompatibility
- Authentication Issues because Basic Authentication is no longer supported by M365 tenant. Only OAuth 2.0 is supported
- Presence of nested folders or labels in Thunderbird does not map correctly to M365
- Incorrect IMAP/SMTP Settings (port number, username, password, etc.) cause connection errors
Wrapping it Up
As there is no direct way to migrate Thunderbird data to Office 365, you can configure Office 365 account in Thunderbird – a workaround to migrate emails only or use Stellar Converter for MBOX Technician– a specialized MBOX to PST converter tool – for full data migration – emails, contacts, calendars – in one go.
How to Migrate Thunderbird to Outlook?
How to Back Up Thunderbird Emails?
FAQ
