The technical migration can be flawless and the project can still fail in the eyes of the people using it, because nobody told them their phone would ask for a password on Tuesday. Communication is not the soft part of a migration. It is the part that decides how many tickets the helpdesk gets on cutover morning.
This post gives a timeline for what to say and when, and templates you can copy, shorten and send. The templates are deliberately plain. Staff do not read long emails from IT.
The rules for every message
Each message should answer four questions in the first three lines: what is changing, when, what you need to do, and who to contact. Everything else is optional. Send from a person, not from a no-reply address, and keep the same sender for the whole project so the messages are recognizable.
Say what will not change as clearly as what will. Most anxiety about a migration is about losing mail, losing contacts or getting a new address. If the address stays the same and the mail comes with them, say so in the first message and repeat it.
- One message per milestone, not weekly updates nobody reads.
- Subject lines that state the action: Your email moves on Tuesday night, restart Outlook Wednesday.
- Screenshots for anything a user must click, especially the MFA setup.
- A named person and a phone number, not a ticket portal, for cutover day.
- The same short FAQ linked from every message.
Timeline
For a migration that runs in batches over a few weeks, each batch gets its own cycle of messages. For a cutover, the whole company gets one cycle.
- Three weeks before: announcement from leadership and IT. What, why, roughly when, what stays the same.
- Two weeks before: MFA registration request with a deadline and screenshots. This is the message that needs a follow-up.
- One week before: the batch schedule by department, and a request to clean up mailboxes and note any shared mailboxes or delegates they use.
- Two days before: reminder with the exact date, what will happen to Outlook and phones, and what to do if something looks wrong.
- Morning of: short confirmation that the move is done, with the three steps to follow.
- One week after: wrap-up, remaining known issues, how to get help, and a thank you.
Templates
Copy these, replace the bracketed parts, and cut anything that does not apply. Shorter is better.
Subject: Company email is moving to Microsoft 365 in [month]
Hi all,
Over the next few weeks we are moving our email from our own server to Microsoft 365. Your email address, your mail, calendar and contacts all stay the same. You will get a couple of short emails from me with dates and steps.
What changes: Outlook will ask you to restart once. Phones need to be signed in again. We are turning on two-step sign-in for everyone.
What you need to do now: nothing. Watch for the next message about two-step sign-in.
Questions: [name], [phone], [email].
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Subject: Action needed by [date]: set up two-step sign-in
Hi all,
Before your mailbox moves you need to register for two-step sign-in. It takes about three minutes and you only do it once.
1. On your phone, install Microsoft Authenticator from the app store.
2. On your computer, go to https://aka.ms/mfasetup and sign in with your work email and your normal password.
3. Follow the prompts to add the Authenticator app. [Screenshot]
Please finish this by [date]. If you get stuck, call [name] at [phone].
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Subject: Your email moves [day] night. Restart Outlook [day] morning.
Hi [department],
Your mailboxes move to Microsoft 365 on [day] evening after 6 pm. Leave your computer on and Outlook closed when you go home.
[Day] morning:
1. Open Outlook. If it asks you to restart, click OK and open it again.
2. Sign in with your work email and password, and approve the prompt on your phone.
3. On your phone, open Outlook and sign in again. If you use the built-in mail app, remove the old account and add your work email again.
Your address, mail, calendar and contacts stay the same. If anything looks wrong, call [name] at [phone] rather than emailing, since email is the thing we are moving.
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Subject: Your move is done
Hi [department],
Your email is now on Microsoft 365. Webmail is at https://outlook.office.com. The three steps from yesterday's message still apply if you have not done them.
Known items we are working on: [list or none].
Thanks for your patience. [name], [phone].The people side of cutover day
Have someone visible. For an office, that means a person walking the floor for the first two hours rather than waiting at a desk. For remote staff, a Teams channel or a group chat that is watched continuously, with a phone number as backup. The first hour produces the same five questions from thirty people; answering them once in the channel saves the helpdesk.
Brief the managers the day before with the same message plus one extra paragraph on what to expect and who to escalate to. They get asked first, and if they can answer the phone question, most tickets never happen.
After the migration
The follow-up message is where you close the loop and set the norms going forward. Point at Outlook on the web and Outlook mobile, remind people that shared mailboxes appear on their own, explain where the archive is if you enabled one, and say plainly what is still being fixed. Then stop sending migration emails. A project that keeps announcing itself after it is done trains people to ignore IT mail, which is exactly the habit you will need to break for the next phishing simulation.
Frequently asked questions
Should the announcement come from IT or from leadership?
The first one from leadership with IT as the contact, because it signals that this is a company change and not an IT hobby. Every later message from the named IT contact.
How do we reach staff who do not read email?
Managers, a printed sheet at shared workstations, and a message in Teams or whatever chat tool is in use. Frontline staff who only use phones need the phone steps on paper.
What is the most common cutover-day question?
The phone. Either it stopped getting mail or it is asking for a password. Put the phone steps at the top of the day-of message and give them to managers in advance.
Takeaway
Tell people what changes, what does not, what to do and who to call, in that order and in few words. Send one message per milestone, brief the managers, and be visible on cutover morning. The templates above are a starting point; the version in your own voice, cut in half, will work better.