Migrate Thunderbird to MS Office 365 with Contacts & Calendar
Quick Answer: You can migrate Thunderbird to an Office 365 account (Business Standard/Basic, Education, or Enterprise) for free via manual Microsoft 365 account configuration in Thunderbird V145+ and then drag & drop. For bulk migration with compliance and complete transfer of emails, address book, and calendar, an automated Thunderbird to Microsoft 365 migration tool or the AzCopy tool can be a faster & more reliable way. This guide gives you step-by-step instructions for all 3 methods.
As you know Thunderbird is a desktop-oriented email client but some professionals find its features too basic according to their requirements. On the other hand, Office 365 is an online business suite, which renders a bunch of advanced features and is capable enough to keep data secure or maintain data securely.
Nowadays, users are choosing to migrate Thunderbird to Office 365 for advanced collaborative features for better email management and it will help you to protect your data if it is confidential. Let us move forward and start learning about the process.
Note: The methods mentioned in this blog will only work with the paid Microsoft email services, which generally have “[email protected]” and not on “Outlook.com” or any other emails which are free personal email account and is not considered an Office 365 (Microsoft 365) account.
Before & After: Thunderbird to Office 365 Migration
Migrating from Thunderbird to Microsoft 365 involves moving Thunderbird local folders with emails & attachments to Office 365 accounts. With the migration you change the way you access, store and manage your data. Here is quick comparison:
| What Changes | In Thunderbird (Before) | In Microsoft 365 (After) |
|---|---|---|
| Storage Location | Local in MBOX format | Cloud on Exchange Online Server |
| Email Access Method | Only on desktop with Thunderbird installation | Cloud sync via Outlook Web/Application on Mobile & Desktop |
| Collaboration Ways | No way to collaborate as meant for personal user | Collaborate with Teams, Shared Mailboxes and Groups |
| Mailbox Limit | No official set limit but Thunderbird monthly release is best for mailboxes under 10GB (recommended by experts & Thunderbird developers) | Increases mailbox size limit of over 50 GB (based on the mailbox license) |
Objectives to Migrate Thunderbird to Office 365
Users want to export Thunderbird to Office 365 for several reasons. Thus, to know the main causes behind that, read the prominent objectives mentioned below:
- Remote access: Users can access Office 365 email from anywhere worldwide using any computer. It asks only for account credentials for login and start accessing the data.
- Auto updates: Thunderbird requires constant updating, whereas there is no need to install the latest updates; it always keeps up to date automatically because it is connected to the web.
- Productivity apps: Office 365 comes with multiple productivity applications that are helpful for growing your business revenue. Like MS word, power BI, exchange online, etc.
- Advanced security: Office 365 is available with effective pricing, and it provides encryption to keep your email data safe and secure. Also, it offers multiple features to manage data.
Functionalities Transferred When You Migrate Thunderbird to Office 365 Mailbox
Although it is possible to import most of Thunderbird data to an Office 365 account, no migration is 100% end-to-end data transfer. Here is a complete list of what you can actually expect to be transferred:
|
✅
Can Be Transferred
|
⚠️
Additional Steps
|
🔒
Not Migrated
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Professional Way to Use Thunderbird to Office 365 Migration Tool
Best in the industry, Thunderbird Converter Tool gives all the freedom to its users to migrate Thunderbird to Office 365, including all email items and attributes. The software has the power to migrate and select Thunderbird data in bulk.
Also, the tool provides a simple and user-friendly interface to all technical and non-technical users. Plus, this Thunderbird to Office 365 migration tool provides dual options to add Thunderbird profile data in the software GUI manually and automatically, which helps in a specific output. Some of the features and working steps of this pro solution are mentioned below in detail:
Brief Guide to Export Thunderbird to Office 365
- Run Thunderbird to Office 365 Migration Tool on your system.
- Now, choose the manual or auto way to add Thunderbird profile data.
- Next, select the required Thunderbird folders and press the Next button.
- Afterward, choose Office 365 from the list of saving options.
- Use advanced settings for Thunderbird to Office 365 migration before starting the process.
- Thereafter, enter your Microsoft 365 account login details and click on Connect.
- The process to migrate Thunderbird to Office 365 is running.
- Emails have been successfully migrated from Thunderbird to Office 365 account.
- Now, log in to your Microsoft Office 365 account and view imported emails.
Benefits of Thunderbird to Office 365 Migration Tool
- Auto File Detection: The software has two options to add Thunderbird profile data automatically from the default storage location.
- Bulk Migration: Users can also use the Select Files or Select Folders button to manually add Thunderbird data. Allowing users to migrate data from Thunderbird in batches with attachments and complete information.
- Targeted Data Migration: The tool previews all the folders and subfolders on the screen so that users can select the required data.
- Direct migration: There is no need to do any import and export process to migrate Thunderbird to Office 365. Users just have to enter the login details of their Office 365 credentials to initiate migration.
- Maintain Folder Hierarchy: Use the Copy to default folders option if you want to merge the same Thunderbird folders with Office 365 folders. After selecting this option, you will get Thunderbird Inbox Data in Office 365 Inbox folder.
- Change Language: The change language option allows you to change the email folder name in multiple international languages, such as English, Dutch, French, German, Spanish, Swedish, Norwegian, Italian, and Finnish.
- Migrate Specific Account: The I am admin option is also helpful to choose a specific user account to migrate Thunderbird to Office 365 account.
- Advanced Compatibility: The tool is compatible with all the latest Windows and Mac Operating Systems. It is even obtainable with the free demo version.
Manual Way to Export Thunderbird to Office 365
There are two manual ways to migrate Thunderbird to Office 365, and thus to know about them in detail, read the below shared conventional solutions:
Method 1: Manual Way for SysAdmins to Migrate Thunderbird to Office 365
For enterprise-scale Thunderbird to Office 365 migration, this method lets one avoid the API throttling limit without sharing Admin or User account passwords. However, this method requires Admin-level expertise (Microsoft 365 Compliance/Global Admin access) as the method involves usage of PowerShell and is not recommended for a limited number of mailboxes. Here are the steps to follow:
- Export Thunderbird emails in PST format using a dedicated tool.
- Go to the Microsoft Purview portal and sign in with the administrator credentials.
- Download the AzCopy tool and SAS URL.
- Upload the PST from Thunderbird to the temporary Azure Storage location with AzCopy.
- Set up the PST import mapping (CSV) file.
- Create a new PST import task via the Network Upload method, then start Thunderbird PST import in Office 365.
Read More: Ultimate Guide to Convert Thunderbird to Outlook
Method 2: Export Thunderbird to Office 365 Using IMAP Settings
If the Thunderbird email application is installed on your computer, then you can use this free method to migrate Thunderbird to Office 365. However, this process is a little lengthy as it has 2 different phases to successfully export Thunderbird to Office 365. The method involves connecting Thunderbird to Office 365 with IMAP settings, then dragging and dropping emails from Thunderbird to Office 365.
As per the latest Thunderbird & Microsoft guidelines – with version 145+ of Thunderbird you no longer need any third party add-on or IMAP connection due to in-built EWS (Exchange-Online Web Services) support. It lets you connect your Office 365 account to Thunderbird directly with OAuth.
Phase 1: Configure Office 365 with Thunderbird
- Run Thunderbird on your device and click on Settings.
- Click on the menu option in the top-right corner.
- Click on Add Mail Account and select “email” option.
- After that, enter your “office 365 credentials.
- Select the “IMAP” option and click on “Continue“.
- Your account will be successfully added to Thunderbird.
Phase 2: Migrate Thunderbird to Office 365
- When the Office 365 account gets added in Thunderbird, it will start reflecting the data on the software panel.
- Next, right-click on any email and choose the New Folder option.
- Further, give it a name and tap on the Select Folder option.
- Then, select the emails or folder you want to add to your Office 365 account.
- Now, drag them and drop them in the configured Office 365 account.
- At last, log in to Outlook 365 to cross-verify and view Thunderbird mails there swiftly.
Consequences: This method becomes extremely time-consuming and hectic for bulk Thunderbird to Office 365 migration. Additionally this method is extremely complex to understand
Phase 3: Import Thunderbird Address Book to Office 365 Account
Note: In Thunderbird, Contacts are stored under Address Books.
- Open Thunderbird Address Book.
- Find the remote Address Book connected to the Office 365 account.
- Open the All Address Books tab.
- Press Ctrl+A to select all contacts.
- Drag & drop them to the Office 365 account.
Drawbacks of Manual Approach
- Complex approach: The method is extremely complex to perform. This may cause data loss and inaccuracies
- Time-consuming: it is extremely time-consuming. The data migration takes two phases, which may take users additional time and effort to understand and perform.
- Data inaccuracy: There is no guarantee of data accuracy. The data may change and get lost during the migration
- No-bulk migration: Users have to repeat the entire process multiple time for each profile. There is no bulk migration support.
Steps to Import Your Thunderbird Calendar into Office 365 Account
Whether you are using the tool, manual admin-level migration solution, or the simple drag & drop, there is no direct way to move calendar data. Here are the manual steps to import Thunderbird calendar into Office 365 during migration:
- Open Thunderbird on your computer.
- Press Alt+3 to open Calendar.
- Click on the three dots near Home under the calendar.
- Choose the Export Calendar option and save it on your PC.
- Sign in to your Office 365 account via Outlook Web.
- Select Calendar in the navigation panel and click on the Add calendar option.
- Choose the “Upload File” option.
- Select the exported file from Thunderbird to import it into an Office 365 account.
Troubleshoot Common Issues When Migrating Thunderbird to Office 365 Account
When importing Thunderbird data into a Microsoft 365 account, users often face the common issues listed below. Here are their possible causes & fixes.
| Issue | Possible Cause | Fix |
|---|---|---|
| Unable to Add Office 365 in Thunderbird | Authentication issue in older Thunderbird versions without EWS support | Upgrade to the latest version and make sure you have a stable internet connection. |
| Data Only Partially Migrated | Thunderbird mailbox exceeds Office 365 storage or throttling limit. | You can increase the storage space on the user license or carry out selective migration.
For limitless bulk migration use BitRecover software. |
| Duplicate Emails | Manual conversion is not exact. | Use dedicated Thunderbird to Office 365 migration software. |
| Missing Attachments | Attachment size exceeds Microsoft 365 mailbox limits (25MB). | Migrate those emails separately. |
What is the Most Suited Way to Migrate Thunderbird to Office 365?
All the methods discussed in the blog are reliable. However, each method has its pros and cons. Use the quick comparison table to identify which method is best for you.
| Factor | Drag and Drop Method | Azure Az Tool – Via PST | Automated Tool |
|---|---|---|---|
| Overall Rating | 3/5 | 3.5/5 | 4/5 |
| Best Use Case | For Limited Emails | 100-1000 user & admin mailbox | Both for bulk & individual level migration |
| Setup & Technical Skill Required | Medium | High – Only for SysAdmins | Low |
| Folder Hierarchy Retention | No | Yes | Yes |
| Contacts & Calendar Migration | Yes via manual addition step | Depends upon PST export | Address books can be migrated directly |
| Time Taken | High-Manual | High-due to setup | Low |
FAQ: How to Migrate Thunderbird to Microsoft 365?
Q: Can I transfer my local Thunderbird data to an Office 365 shared mailbox?
Yes, but with a manual method via drag and drop – you need to have the shared mailbox added to your O365 account with the required permissions. With the admin-level AzCopy tool or BitRecover Thunderbird to Office 365 Migration tool you can carry out direct migration.
Q: Can I transfer my Thunderbird emails to M 365 without account configuration in Thunderbird?
Yes, follow the manual steps in case you have limited or specific emails that you want to transfer from Thunderbird to Office 365:
- Open Thunderbird on your computer.
- Browse and right-click on the Thunderbird email that you want to export.
- Click on the Save As option and choose .eml files to convert Thunderbird to EML files.
- Open MS Outlook on the very same device.
- Make sure that Outlook has your Office 365 account configured in it.
- Drag and drop the saved .eml file into any desired Outlook folder.
- Wait for a while so that Outlook data automatically syncs with Office 365.
But in case you are dealing with bulk emails and you cannot configure your Office 365 account in Thunderbird (due to a crash or authentication issue) – you can also use automated solutions.
Q: How long does it take to migrate a large Thunderbird mailbox (e.g., 20GB+) to Office 365?
The time taken for Thunderbird to Office 365 may vary based on the method used and internet speed. It can take anywhere between several hours to days. The PowerShell route helps avoid throttling, hence it is relatively faster. But you can also use the BitRecover Thunderbird to Office 365 Migration tool in case you want to speed up the process without technical expertise.
Q: I have configured multiple accounts in Thunderbird. Will your software allow me to migrate all accounts to Microsoft 365?
Yes, select the “I am converting multiple users” option when adding Thunderbird profile data in the software panel. The tool is capable of migrating Thunderbird emails to Office 365 from several configured accounts.
Q: Can I delete my Thunderbird emails after I import Thunderbird data into my O365 account?
Yes, the process involves permanent import of Thunderbird data into an Office 365 account. It is not an active sync; you can easily delete your emails afterwards.
Q: Do these steps remain the same for personal or family subscription accounts?
Personal or family subscription accounts are merely Outlook.com accounts – although the manual drag & drop method remains the same. The Azure Tool is bound to fail and in the BitRecover Tool interface under the destination you need to select Outlook.com instead of Office 365.
Conclusion
In the above blog post, we have explained the step-by-step process to migrate Thunderbird to Office 365 via 3 different techniques. These are 100% verified methods, we have tested all the above-mentioned approaches in BitRecover Lab before suggesting them to anyone. If you have any other doubts that we have not covered in this blog, feel free to connect with our support team.
