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How to Migrate Proton Mail to Office 365 – 2 Simple Ways

Published By Aldrich Calvin
Anuraag Singh
Approved By Anuraag Singh
Published On November 2nd, 2023

The privacy-focused Proton Mail lacks the critical tools that any business requires nowadays. Therefore, the need to migrate Proton Mail to Office 365 emerges naturally. Although proton mail is kind enough to provide an export tool free of cost, the tool is limited in scope and has no migration capability. 

So, as a result, we prepared this write-up to answer all of the user queries. Additionally, we provide them with a clear pathway to move their data away from proton mail and into the feature-rich Office 365 environment. Let’s begin by exploring the reasons for such a change.

Table of Content

Why Perform Proton Mail to Office 365 Migration? 

Proton Mail is world-renowned for its security features. Moreover, its data centers are located deep within the Swiss Alps, combine that with strict privacy laws, and you get bulletproof data security. However, the fact of the matter is, that privacy alone is not enough to choose a webmail service. Therefore, given below are some of the reasons that force users to leave Proton mail.

  • Lack of Features – Office 365 is not just a mailing service it’s an all-in-one business productivity tool, with options to communicate through Teams, store large amounts of data in Onedrive, and maintain servers via Exchange Online. All of these features are toned down or outright missing in  Proton Mail.
  • Limited Storage – The free version of Proton Mail only offers a measly 500 MB of data. You do not need an expert to figure out how this limits your communication. Moreover, the premium versions fail to compare to the unlimited storage that Office 365 offers in its subscription.
  • Absence of Tools – Proton Mail also does not have any inbuilt alternative to Word, Powerpoint, or Excel all of which have become synonymous in the daily use in ‌ any organization.

Read More: The Means to Migrate Calendar from G Suite to Office 365 Effectively

Apart from this regular updates and the freedom to pay for only what you use make Office 365 a better alternative in every single way. So let’s get straight to the automated tool to help you transfer your webmail data.

Professional Method to Migrate Proton Mail to Office 365

The only solution you ever need is the SysTools IMAP to Office 365 Migrator. Its “user first” policy is shown by the simplistic and easy-to-navigate UI. Moreover, the tool has inbuilt systems to make migration a quick and error-free experience for all users regardless of technical expertise. Follow the steps below and experience the best way of Proton Mail to Office 365 migration.

Step 1. After installing the tool on your workstation, open it and pick IMAP and Office 365 as source and target respectively. 

Open Tool

Step 2. In the Workload section below check the option next to emails and apply the date filter and proceed ahead.

Add Date Filter

Step 3. Then, move on to the source page choose Other from the IMAP server dropdown, and fill in other info as prompted by the tool

Validate Source

Step 4. Validate the admin credentials which include both email and application ID then press Next. 

Validate Destination

Step 5. Attach the CSV file with the user info directly, or make changes in the template provided in the tool and reupload it.

Attach Users

Step 6. Finally, get a preview of all users select the ones whose data needs to be shifted then validate and hit Start Migration. The tool does the rest of the work automatically.

Start migration

Next up we discuss an alternative way to move proton mail data. Before starting with the transfer methods, there are a few steps a user must complete first.

Manual Method for Transferring Proton Mail Data to Office 365

A few additional requirements of the semi-manual process are as follows

  • Install the Proton Mail Import-Export App.
  • Download ‌MBOX conversion Software.
  • Get the Outlook for Desktop version for your PC.

Now we are ready to complete the switching of Proton’s email data manually

The manual method is not a direct transfer so we have broken down the entire process into three stages.

Stage 1. Use Proton Import Export Application

Step 1. Launch the Protonmail Import Export App and click on the Add Account option.

Launch Proton Import Export

Step 2. Then, sign in with your Proton Mail credentials and hit the Next button.

Enter Credentials

Step 3. Once the STATUS is “connected” click on the Export All option.

Export All

Step 4. Then, press the Export button to continue.


Step 5. Mark folders, apply the date filter and pick the MBOX format. Select a place to save the email data and click the Export button.

Configure Settings

Step 6. Once the export is completed, press the Okay button.

Click Okay

Step 7. View and verify your MBOX files at the location you selected this marks the end of the first phase of Proton Mail to Office 365 migration.

Locate MBOX

Stage 2. Convert the MBOX Data to PST File Format

For this download the tool from the link given below.

Then follow these steps.

Step 1. Open the Professional Utility, then click on the Add file option.

Open Tool

Step 2. In the window that pops up MBOX Files are selected by default. Just press Next.

Choose MBOX

Step 4. Browse for your MBOX file using () and hit Process.


Step 5. Then, you will get a preview of the emails. Mark the box next to the desired File and click on the Export button from the top menu.


Step 6. A window opens select the folders, export format (PST), browse for a location, and click Export.

Convert & Export

Step 7. On the pop-up indicating a successful export appears click on OK to proceed.

Confirm Export

Step 8. Finally, examine and confirm your PST documents you are now one step closer to migrating Proton Mail to Office 365.

View PST

Stage 3. Attach the PST file to Outlook Client

  • Step 1. Open Outlook, and click on the File tab at the top menu bar.
  • Step 2. Then, under the Open section, select the Import option.
  • Step 3. Select the ‘Import from another program or file’ option in the Import and Export Wizard and hit ‘Next’.
  • Step 4. Select Outlook Data File (.pst), and then select Next.
  • Step 5. Then, directly enter the location and filename of the .pst file you wish to import or browse to locate the file to be imported. Once done press Next.
  • Step 6. Finally, choose the folder you wish to import and hit the Finish button to complete the process.

Source: How to manage .pst files in Microsoft Outlook

Although the manual method is complete there are a few limitations that users must be aware of if they choose this way.

Limitations of Manual Method

  • Time-consuming – Installing, configuring, and navigating through three different programs is a time-consuming affair. Instead of this users can directly migrate their Proton Mail data to Office 365 via the professional migrator.
  • Error Prone – The constant shifting of data may induce unwanted corruption. Moreover, these errors may permanently damage some critical files requiring the users to start the process from scratch. At the same time, the automated utility encounters no such issues and even has a delta migration facility.
  • Slow and Repetitive – Another major limiting factor of not using the advanced tool is that you have to export the data of each user individually.

Also Read: How to Transfer Emails from Bluehost to Office 365 In a Effortless Way


In this article, we discussed two separate ways to migrate Proton Mail to Office 365. Out of these, the Automated tool is the clear-cut winner. Additionally, by direct transfer to the Office 365 environment, bypasses the need ‌for file conversion entirely. So make the smart choice and go for the tool and lay rest to all migration-related woes.