
Users and businesses prefer Microsoft 365 (Office 365) for its flexibility, advanced data security measures and collaborative tools like Outlook, Skype, OneNote, etc. However, its biggest advantage over other email clients is that it allows users to access their mailbox data anywhere, anytime and from any device connected to the internet.
Because of these benefits, many users and businesses look for ways to transition from on-premise / device restricted email clients such as Thunderbird, Apple Mail, Entourage, etc., to Office 365.
But when users try to migrate their mailbox data from email clients like Thunderbird, Apple Mail, etc., to Office 365, they are unable to make the switch. This is because the above email clients use the MBOX file format to save files while Office 365 uses the PST file format. Apart from incompatible file formats, there are no direct methods to transfer MBOX to Office 365.
In this post, we will look at some ways to migrate MBOX to Office 365.
How to transfer MBOX to Office 365?
Office 365 doesn’t support the MBOX file format. However, it supports PST file format to import mailbox data into it. Hence, if you have are trying to migrate mailbox data from an MBOX compliant email client to Office 365 (Microsoft 365) , you will need to convert the MBOX files to PST files using a specialized MBOX to PST converter software.
Once you have successfully converted the MBOX file/s to PST file/s you can use either Drive shipping or Network upload to migrate a large number of converted PST files in a single operation.
However, there is also a simple way to do so. For this, you can use an advanced tool such as Stellar Converter for MBOX Technician that can help you directly import the converted file/s into Office 365.
Let’s look at these methods in detail.
Method 1: Migrate MBOX to PST via Drive Shipping or Network Upload
If you want to transfer data from multiple MBOX files into Office 365, you will need to first convert them to Outlook importable PST file format. For this, you can use a third-party MBOX to PST converter that allows you to convert an MBOX file to Outlook/Office 365 compatible PST file format.
After converting the MBOX files to PST, you can use Microsoft recommended methods to migrate large number of PST files to Office 365. To do this, Microsoft recommends using either Drive Shipping or Network Upload.
Drive Shipping: Drive Shipping is a method which users can use to migrate bulk PST files to Office 365. Users will have to transfer all the PST files on a BitLocker-encrypted hard drive and physically ship it to a Microsoft data center. A data center expert will copy and upload all the PST files to a Microsoft Storage. From their, you can migrate the PST files into Office 365.
Network Upload: Another method recommended by Microsoft to migrate large number of PST files to Office 365 is Network Upload. It is a lengthy method where users will have to upload all the PST files into a temporary Microsoft Cloud and then use the mapping sheet to import the uploaded PST files to Office 365.
Limitations of manual methods
Here are the limitations to the above above methods:
- They are time-consuming.
- Drive shipping is costly as user will have to purchase the hard drive, pay the shipping costs and pay a per GB data transfer cost to Microsoft for transferring PST files to a temporary cloud storage.
Method 2: Use an MBOX to PST Software
If you want to transfer multiple MBOX files to Office 365 then the above methods are suitable. However, if you have a single or a handlful of MBOX files that you want to transfer to Office 365, you can simplify the process and quickly migrate the MBOX files to Office 365 using Stellar Converter for MBOX Technician.
It is a powerful MBOX to Office 365 converter that efficiently converts and migrates mailbox data of various MBOX-compatible e-mail clients like Entourage, Apple Mail, Thunderbird, Eudora, etc., to Office 365.
Here are the steps to use this software to convert the MBOX to PST:
Step 1: Download and install Stellar Converter for MBOX from its official website.
Step 2: Once you launch it, you will see the Select MBOX window. Use the drop-down menu against the Select Mail Client option to select the e-mail client.
Step 3: After selecting the e-mail client, click on either Select File or Select Identity. Then, click on Convert.

Step 4: The software will start scanning the selected MBOX file. Once the scan is complete, preview the MBOX data.

Step 5: If you are satisfied with the conversion results, click on the Save Converted File button under the Home tab.

Step 6: Choose the Export to Microsoft 365 option in the Save As window. Click Next.

Step 7: In the next window, Select M365 Profile configured with Outlook, to export the converted data to Microsoft 365 (O365). After selecting the correct Profile click on Save.

Step 8: After selecting the correct Profile click on Save.
Step 9: The software will migrate the PST file data to the Office 365 account. Once the process is complete, click OK.

Conclusion
For users transitioning from an MBOX-compatible e-mail client to Office 365, it becomes a challenge to make the switch due to certain limitations – the lack of any direct methods and Outlook not supporting the MBOX file format.
While Drive Shipping and Network Upload can help you migrate large number of MBOX files to Office 365, they are time-consuming and resource intensive.However, using an MBOX to PST converter – Stellar Converter for MBOX Technician – can simplify the mailbox conversion process and help you switch to Outlook or Office 365 without any hassle.
Related Article: 4 Ways to Fix PST Files That Cannot Be Opened in Outlook