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Target audience: Students

Gmail: migrating mail to Office 365 on Windows (Thunderbird)

The UU will make the transition from Gmail to Office 365 and Outlook for all students this year. This manual is meant for all current UU students who will be affected by this change. Below you will find instructions about how to transfer mail from your old Gmail address to your new inbox.

In order to follow these instructions, it is necessary to install Thunderbird. Due to technical limitations Outlook cannot be used to open Gmail once mailing has been disabled.

  • Part 1: Preparations
  • Part 2: Connecting Gmail
  • Part 3: Connecting Outlook
  • Part 4: Migrating mail
  • Step 1

    Part 1: Preparations

  • Step 2

    Go to https://www.thunderbird.net/ and download the Thunderbird installation file.

  • Step 3

    Open the installation file and follow the on screen instructions.

    NOTE: Uncheck the Use Thunderbird as my default application box.

  • Step 4

    Part 2: Connecting Gmail 

  • Step 5

    Thunderbird will ask you to set-up an mail account.

    • Enter your students mail and password
    • Click Configure manually

  • Step 6

    Use the following settings and click Re-test:


    • Protocol: IMAP
    • Server: imap.gmail.com
    • Port: 993
    • SSL: SSL/TLS
    • Authentication: Autodetect
    • Username: your student mail address


    • Protocol: SMTP
    • Server: smtp.gmail.com
    • Port: 587
    • Authentication: Autodetect
    • Username: your student mail address

  • Step 7

    After click Re-test you will need to change the authentication method.

    • Select OAuht2 as authentication method and click Done.

  • Step 8

    You will get a sign in screen from the Utrecht University

    • Sign in with your email address and password.

  • Step 9

    A Google pop-up will ask your permission to give Thunderbird access to your mailbox.

    • Click Allow

    Your Gmail mailbox is now configured.

  • Step 10

    Part 3: Connecting Outlook 

  • Step 11

    Below the header Choose What to Set Up at the Thunderbird welcome screen is the option to add another account.

    • Click Email

  • Step 12

    • Enter your student email address and password
    • Click Continue

  • Step 13

    • Select Exchange as the protocol
    • Thunderbird will ask to install an add-on. Click Install

    NOTE: The add-on is free to use for the first month. If you want to continue using Thunderbird after this process it will cost  €10 each year.

  • Step 14

    You will get a sign in screen from the Utrecht University

    • Sign in with your email address and password.

  • Step 15

    Both mailboxes are now connected to Thunderbird

  • Step 16

    Part 4: Migrate mail

  • Step 17

    Thunderbird should automatically retrieve all messages. If not, you can click Get messages in the top left corner.

  • Step 18

    If you used Labels in Gmail, you will need to recreate the folders in Outlook and copy the mail for each folder. It is not possible to copy the Gmail folder structure.

  • Step 19

    • Select the messages you want to copy. It is advised to copy your mail in several batches to minimize the chance of errors.
    • Open the context menu by clicking with the right mouse button on the selected emails.
    • Select Copy to
    • Select the preferred folder in you Outlook mailbox.

  • Step 20

    Thunderbird will now start copying your messages. This will take longer as you select more messages at once. Wait until Thunderbird is finished copying before resuming to copy the next batch.

  • Step 21

    • Check if your messages are copied to your Outlook mailbox by signing in to https://outlook.office.com
    • If everything is correct, you can remove Thunderbird from you computer.


Last modified: 6/08/2020

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