Universiteit Leiden

nl en


Mail migration from Outlook to Exchange Online

14 March 2022

The Faculty of Science will step by step use the new mail environment Exchange Online. Your Outlook mailbox and calendar will transfer to Exchange Online. The shared 'functional' mailboxes will also be migrated. Do you only use a personal mailbox and calendar in Outlook? If so, you do not have to do anything yourself. If you want to keep using email and calendar on another device such as a smartphone, you need to take action. The migration process takes place in the background and your mailbox and calendar will remain available.

Why are we migrating to Exchange Online?

The transition to Exchange Online makes it possible to integrate Office 365 applications and to use new apps, such as the Outlook app, Planner and To Do. Security will be increased and better protection will be offered against phishing emails. The size of the mailbox will expand, so it is no longer necessary to send individual requests to expand the mailbox.


The planning for the migration is as follows:

Date Institute
21 March 2022 CML
Hortus Botanicus
Lorentz Center
28 March 2022 LIC
4 April 2022 LACDR

For the LIACS, MI, LION and the Leiden Observatory a separate planning will follow. As soon as more information is available, an update will be sent.

The migration is expected to be completed by 10.00 AM on Monday 21, 28 March and 4 April. During this period you can continue to work as usual.

How can I prepare for mail migration?

  • You may have linked other mailboxes in addition to your own mailbox. Make sure to note down the name of this mailbox beforehand so that it can be added again after the migration.
  • Download the Outlook app for your mobile if you want to synchronise your mail, calendar or contacts. You can find this in the Play Store (for Android) or the App Store (for iPhone)

What will I notice after the migration?

  • Your regular mailbox, archive folders and agenda on your university (managed) PC or laptop are automatically transferred to the new mail environment and are immediately available in Outlook. It may take some time before your online archive is available. Mailboxes that you manage in addition to your own mailbox, so-called functional (or shared) mailboxes, are no longer linked and must be added again. You can find information on how to add these functional boxes to your account in the Helpdesk portal.
  • You can now also use the Outlook app on your phone, tablet or own device. You can also continue to use your current mail app, but you will then have to link your mailbox again. This also applies to other operating systems such as Mac and Linux. Do not forget to delete the old account first.
  • You can find your webmail in your browser if you log in to office.com and then choose the Outlook Online app.
  • Should you have to log in again, it concerns an Office 365 login and you will also be asked for your MultiFactor Authentication.
  • If an email has been sent to you that is considered suspicious by Microsoft (spam, fishing, etc), you will receive an email informing you that one or more messages have been placed in quarantine. The mail is repeated every three days. The sender of this message is: quarantine@messaging.microsoft.com. You can still access these emails in a separate quarantine environment.

Extra information if you use a functional mailbox

Functional mailboxes are widely used. The functional mailboxes will be migrated together with the regular mailboxes of the institute. When a functional mailbox is used within an institute it does not cause any problems if the functional mailbox is added after the migration. A functional mailbox used by staff from other institutes or support staff may be temporarily inaccessible to staff who's mailboxes have not been migrated. If this is the case, please contact the ISSC.


If you have any problems as a result of the migration, please contact the helpdesk. This can be done in the following ways;

1. Send us an e-mail at: (helpdesk@issc.leidenuniv.nl ) or,
2. Contact the helpdesk via the helpdesk portal

This website uses cookies.  More information.