So you’ve made the decision you’re going to Office 365. We believe you won’t regret it. Just to make sure, here are some suggestions for a smooth and successful transition and which Office 365 Migration Tools You Should Consider.

A key is to remember that because a lot of your users are not IT specialists and they rely on you to ensure that changes won’t have a damaging effect. So long as you take care to dot the I’s and cross the T’s, there’s no reason you shouldn’t achieve the ideal migration, which is one that is so transparent that, if users notice it at all, they see it as an upgrade and an improvement in service.

How to make your move to Office 365 go smoothly

Main Office 365 migration routes

There are, in essence, three main ways to achieve successful migration and the first two will depend on whether or not you are using Microsoft Exchange. Here are the three:

  1. Exchange to Office 365 using Exchange/Office 365 tools
  2. Other email service to Office 365 using Office 365 tools
  3. Migration using third party tools

Exchange to Office 365 using Exchange/Office 365 tools

You’ll find Microsoft’s advice here. There’s a handy reminder there to check the limits to Exchange Online, because they vary between plans. You’ll find the limits on twelve separate facets of the system here. It’s worth taking a look – in fact, you should – just to make sure that the plan you’ve chosen provides enough for all your needs, both now and in the foreseeable future.


All plans come with unlimited retention time for the deleted items folder and 30 days retention for the junk mail folder. This may not suit your organisation’s policies – you can change it.

Who migrates mailbox contents – the administrator or the user?

Microsoft also allows you to choose between:

  • Having the administrator migrate (from an existing on-premises Exchange Server environment), all email, calendar, and contacts from user mailboxes to Office 365; or
  • Setting up new user mailboxes on Office 365 and allowing users to import contacts, calendar and emails.

Choosing the second of those options might not win you a huge fan base among non-technical users; leaving non-technical users to import into a new mailbox often gives rise to a constant stream of “how do I do this?” queries, at which point you may feel that total migration by admin would have been the way to go.

The three possible Office 365 migration methods

  1. Cutover Migration
    Cutover Migration transfers all mailboxes at the same time. If you have fewer than 2,000 mailboxes, this is the way to go. Microsoft provides a set-up wizard that will transfer up to 150 mailboxes at a time, but there’s an Exchange Admin Centre (EAC) that will move all 2,000. What you need to know before starting EAC is here, and one of the most important things you need to know is that, while EAC will transfer up to 2,000 mailboxes, it takes such a long time that you’re probably better off using the set-up wizard and you’ll find details on how to do that here.
  2. Staged Migration
    Staged migration won’t work if you’re currently using Exchange 2010. However, if you’re on Exchange 2003 or Exchange 2007, with more than 2,000 mailboxes, follow the instructions you’ll find here to move your mailboxes in batches. You may want to bear in mind that, if you’re using Unified Messaging, it won’t work during the transfer – turn it off before beginning migration and turn it on again when migration is complete.
  3. Hybrid Migration
    As well as the first two options, it’s possible to make migration a much more gradual thing, so that for a period you can have both online and on-premises mail boxes – provided that you have Exchange 2013, or run exchange 2010 with between 150 and 2,000 mailboxes, or have Exchange 2010 and simply want to take things slowly. Do this by using the Exchange Server Deployment Assistant.

Other email service to Office 365 using Office 365 tools

This is a little more complicated, but as long as you follow the procedure step-by-step it shouldn’t cause great difficulty – as long as you are migrating from Gmail, Exchange, or another email system that supports IMAP migration. Instructions are here and there are some limitations:

  • You must first set up a mailbox for each user, because IMAP (Internet Message Access Protocol) migration doesn’t create mailboxes in Office 365
  • Once the mailboxes are set up, IMAP migration will transfer to them the contents of the inbox and other mailboxes (to a maximum of half a million items, with the newest taking precedence, and no email larger than 35Mb will be migrated), but not the calendar, contacts and tasks – users have to transfer those themselves
  • Migration is not transparent to users, so when it’s done you’ll need to tell them how to access their new mailboxes

Automating migration using Office 365 tools

The tools we’ve looked at so far are the tools that Microsoft provides. The company does not have the field to itself.

Code Two Office 365 Migration

The interface for Code Two’s migration tool is slick. Starting with a screen that looks like this:

Which Office 365 Migration Tools - screen grab

you’re taken through a series of clearly worded, understandable questions to hook up your source and target servers. Our verdict on the Code Two tool would be: it does exactly what it says it’s going to so and it does it as though it had talked through with you in advance exactly how you’d like a migration to work.


We just gave the Code Two tool a pretty clean bill of health. The object was not to say, “Buy Code Two,” and nor do we plan to comment on each individual tool that’s out there – our intention was to say, “There are some third party tools, by-and-large they will do a good, smooth job for you, and Code Two is one of them. Other available tools (and his list is not exclusive) are:

Any of these is likely to do the job for you, and do it well, and it could be that the way to choose which is right for you is to Google reviews for each of them and see which approach and interface you feel happiest with. Or, of course, you can come to us – because, for most people, migrating is something they’ll do only once, and you may feel a little more secure if you’re doing it in partnership with people for whom it’s become routine.

Considering an Office 365 Migration?
Speak to the experienced team at Stanfield IT on 1300 910 333