Moving company email to Outlook without losing messages

Moving email rarely ends in disaster, but when it does, it is always for the same reason. It is worth knowing it in advance, because after the fact there is usually nothing left to save.

One setting that loses the archive

Email can be downloaded in two ways. With one, messages stay on the server and every device sees the same thing. With the other, older one, the program downloads messages to the disk and deletes them from the server.

If the company used the second method for years, the whole archive sits on a single computer only. It is not in the cloud, it is not on the phone and no provider can restore it. That is why the first step in a migration is always to check which mode the old mailbox works in, and the second is to back up what is on the disk.

An order that does not hurt

• A copy of the archive from the old program to a file. Before anything else.
• Creating the mailboxes with the new provider, but without switching the mail over.
• Copying messages between the mailboxes while both run in parallel.
• Only now switching mail routing to the new provider.
• A few days of keeping an eye on the old mailbox, because some messages will still arrive there.

Switching mail routing does not take effect immediately all over the world. For a while, some messages still travel the old way, which is why the old mailbox has to stay alive during that time.

Three records that people forget

When changing provider, you have to update the records in your domain that tell the world who is allowed to send email on your behalf. Without them, messages start landing in recipients' spam folders, and with no warning on your side.

• SPF lists the servers authorised to send. It must name the new provider and stop naming the old one.
• DKIM signs messages with a key. The new provider generates the key, and it has to be added to the domain.
• DMARC says what to do with a message that has failed the two previous checks. You start in monitoring mode and tighten it only when the reports are clean.

Small things that spoil the first day

• Signatures. They copy badly, and the simplest way is to set them up again, once, for everyone.
• Rules that sort mail into folders. They usually do not move together with the email.
• Calendar and contacts. That is a separate export, it does not travel with the messages.
• Common mailboxes, for example the office or the service desk. It is worth setting them up as shared mailboxes, not as an account whose password six people know.
• Devices that send email on their own: a printer with scan-to-email, a form on the website, a warehouse system. Each of them has the old login details stored somewhere.

How long it takes

For a few mailboxes of reasonable size, it is usually one working day, most of which is waiting for the messages to copy. With large archives, copying starts in the evening so that everything is in place in the morning.