Microsoft 365 Email Migration for UK Small Business

Most small firms do not think about their email until something forces them to. The website provider changes their packages. The webmail looks dated and keeps logging you out. A client says your replies are landing in their spam folder. Or you just want Outlook, a shared calendar and email that works properly on your phone.

That usually points to one job: moving your email to Microsoft 365. This guide explains what that migration involves for a small UK business with one or two mailboxes, what a professional actually does step by step, and what it costs to hand the whole thing over.

Quick answer:

• You can move your email to Microsoft 365 and keep the exact same address.
• All your old emails, folders and sent items come across. Nothing is deleted from the old system during the move.
• The switch is done in a set order so there is no real downtime. New mail keeps arriving throughout.
• A single mailbox move is usually done within a day or two, including checks and testing.
• You do not need to move your website. Email and website hosting are separate things.

What you are actually moving

Before the move makes sense, it helps to know what you have now. Most small business email that was "set up by the website company" works like this.

• Your domain, such as yourcompany.co.uk, is registered with a domain registrar.
• Your DNS records point that domain at services. One record, the MX record, says where email should be delivered.
• Your mailbox lives on a mail server at your hosting company. That is where your messages are stored.
• Roundcube or "webmail" is just a website for reading that mailbox in a browser. It is not the mailbox itself.

People often think Roundcube is their email. It is not. It is one window onto a mailbox that sits somewhere else. When we migrate you, we are copying the contents of that mailbox to a new one on Microsoft's Exchange Online, then pointing your domain at Microsoft instead of the old host.

Your website is not part of this. If your site is hosted with the same company, it stays exactly where it is. Only the email-related DNS records change.

Can I keep my email address?

Yes. This is the most common worry and the answer is simple. Your address is tied to your domain, not to your current host. As long as you own the domain and can reach the account that controls its DNS, your address moves with you. info@yourcompany.co.uk stays info@yourcompany.co.uk.

The same applies to extra addresses and aliases. If you have info@, accounts@ and a catch-all that forwards everything else, all of that can be rebuilt in Microsoft 365.

Will I lose my old emails?

No. A migration is a copy, not a move. We connect to your old mailbox, read every folder, and copy each message into the new Microsoft 365 mailbox. The old mailbox is left untouched until you are happy everything has arrived.

This works through a standard method called IMAP, which nearly every hosting mailbox supports. It brings across your inbox, sent items, drafts and every folder you have made, along with attachments. Contacts and calendars kept inside webmail need a separate export and import, so it is worth mentioning those if you use them.

One thing to know: very large mailboxes take longer. A mailbox with fifteen years of history and thousands of large attachments is a bigger job than one that has been kept tidy. It still works, it just needs more time and a closer check at the end.

What a professional does, start to finish

Here is the actual process for a single-mailbox move, in plain English. A good engineer follows this order because it is what keeps your mail flowing the whole way through.

1. Check what you have

We confirm where your domain is registered, who controls the DNS, whether you can sign in to those accounts, how big the mailbox is, and that IMAP access is switched on at the old host. Five minutes of checking here prevents surprises later.

2. Set up Microsoft 365 without touching live mail

We create your Microsoft 365 tenant, add your licence, and add your domain to the account. At this stage nothing has changed for you. Mail still flows to the old host as normal.

3. Prove you own the domain

Microsoft asks you to add one TXT record to your DNS to confirm the domain is yours. This record does not affect mail. It just unlocks the domain inside your Microsoft 365 account.

4. Build the new mailbox

We create the Exchange Online mailbox for your address, plus any aliases and shared mailboxes you use.

5. Lower the DNS TTL

TTL is how long other mail servers cache your settings. Lowering it a day before the switch means the change spreads across the internet in minutes rather than hours.

6. Copy the mail across

We run the IMAP migration from the old mailbox into Microsoft 365. This can run in the background while you carry on working. Depending on size it takes anywhere from twenty minutes to several hours.

7. Check the copy is complete

We compare folder counts, spot-check sent items and open a few attachments. If anything is short, we run the sync again before going any further.

8. Switch the MX record

Now we change the MX record so new mail is delivered to Microsoft 365 instead of the old host. From this point, new messages land in your new mailbox.

9. Update SPF, DKIM and Autodiscover

We update SPF so your outgoing mail is trusted, switch on DKIM and publish its two records so your mail is signed, and set Autodiscover so Outlook and phones connect automatically. More on these below.

10. Keep the old mailbox as a safety net

We leave the old mailbox live for a short while. If any message slipped through during the switch, it is caught there and can be moved across.

11. Test everything

Send and receive in both directions, set up Outlook on your computer, connect your phone, check webmail, and confirm your signature and aliases work.

12. Hand over

You get your sign-in details, multi-factor authentication set up on your account, a quick walkthrough of Outlook, and a short window afterwards to catch anything small.

The DNS records, explained simply

Four record types matter for email. You do not need to understand the syntax, but it helps to know what each one is for, because a mistake in any of them causes the delivery problems people dread.

• MX tells the world where to deliver mail for your domain. After migration it points at Microsoft.
• SPF is a list of servers allowed to send mail as your domain. If Microsoft is not on the list, your mail can be marked as spam or rejected. Old entries for the previous host should be removed once they are no longer used.
• DKIM adds a digital signature to every message you send, so receiving servers can confirm it really came from you and was not tampered with. Microsoft gives you two records to publish. You can read Microsoft's own guide to setting up DKIM in Exchange Online.
• Autodiscover is a convenience record. It lets Outlook and mobile mail apps find your mailbox settings automatically instead of you typing in server names.

Microsoft publishes the full list of records it needs. The values are unique to your domain, which is why you will not find copy-and-paste settings that work for everyone.

Will there be downtime?

Done in the right order, no. The mail is copied before the MX record changes, so nothing is lost in the gap. During the short window while the MX change spreads, a message might land in the old mailbox for a few minutes. That is why the old mailbox stays live as a backstop and gets checked afterwards.

Where people run into trouble is doing the steps out of order, usually switching the MX record first and migrating the old mail afterwards. By then the old mailbox has stopped receiving anything new, and the two mailboxes have drifted apart. The fix is simply to follow the sequence.

We normally do the switch during working hours so we can watch it settle and test straight away, rather than leaving it running unattended overnight.

How long it takes and what it costs

For a single mailbox, most of a working day covers it, spread across the copy, the DNS changes and the testing. Two or three mailboxes is still usually a one-day job. The things that push it longer are a very large mailbox, a domain where nobody has the login, or a setup with lots of aliases, forwarders and rules to rebuild.

On price, some IT firms quote £900 or more for a single mailbox move. We think that is steep for what it is. Verge Tech gives you a fixed one-off price after a quick look at your current setup, with no ongoing support contract attached. You will also need a Microsoft 365 licence, which you can buy yourself or we can set up for you. Business Basic suits firms that live in webmail and a browser. Business Standard adds the installed Outlook, Word and Excel apps.

If you are still weighing up providers and setup in general, our guide on how to set up business email on your own domain covers the wider decisions.

Why Microsoft 365 beats hosting-company email

Shared hosting email is fine until your business depends on it. Then the gaps start to matter.

• Control. You get a proper admin account. You can add and remove mailboxes, reset passwords, and lock an account the moment someone leaves. With hosting email that often means raising a support ticket and waiting.
• Security. Multi-factor authentication, built-in filtering against phishing and malware, and the option to add tighter rules as you grow.
• Reliability. Microsoft's mail platform is built for business use, with far better uptime than a shared server running hundreds of other sites.
• GDPR and leavers. When a staff member leaves, you can keep their mailbox, convert it to a shared one, or export it for your records. That clean handover is much harder on hosting email, and it matters if you ever have to show how you handle data. The ICO expects businesses to have that kind of control.
• The tools around it. Shared calendars, Teams, OneDrive and a single sign-in for the whole team, all under one licence.

Should I do it myself or hire someone?

A confident owner can move a single mailbox. The Microsoft side is well documented and the IMAP copy is a guided process. The risk is not the setup screens, it is the DNS. A wrong SPF entry or a half-finished MX change can stop mail for your whole domain, and by the time you notice, clients have already had bounces.

Most people who call us have either tried and got stuck at the DNS stage, or simply do not want to be the person responsible if a client email goes missing. Hiring someone for a fixed price buys you the right order, the checks, and someone to call if something looks off in the first week.

Frequently Asked Questions

Can I move my email from cPanel to Microsoft 365 and keep the same address?

Yes. Your address belongs to your domain, not your current host. As long as you own the domain and can access its DNS settings, the address stays the same after the move to Microsoft 365.

How long does a small business email migration to Microsoft 365 take?

A single mailbox is usually done within a working day, including the copy, the DNS changes and testing. Larger mailboxes with years of history and big attachments take longer, mainly because of the time needed to copy and verify all the data.

Will I lose old emails when moving from Roundcube to Outlook?

No. Roundcube is only the webmail screen for a mailbox that lives on your host's server. The migration copies that mailbox, including every folder, sent items and attachments, into Microsoft 365. The old mailbox is left in place until you confirm everything arrived.

What DNS records do I need for Microsoft 365 email?

You need an MX record pointing at Microsoft, an SPF record listing Microsoft as an allowed sender, two DKIM records to sign your outgoing mail, and an Autodiscover record so Outlook and phones connect automatically. Microsoft generates the exact values for your domain.

Do I need to change my website hosting to use Microsoft 365 email?

No. Email hosting and website hosting are separate. Your website stays where it is. Only the email-related DNS records change during the migration.

How much does it cost to migrate one mailbox to Microsoft 365 in the UK?

Some firms quote £900 or more for a single mailbox. Verge Tech gives a fixed one-off price after a quick look at your setup, with no ongoing contract. You also need a Microsoft 365 licence, from around £6 per user per month for Business Basic.