Email Migrations to Office 365 | Lessons Learned

I’m back! I’ve been away for the past few months focused on email migrations for a few companies that we’ve recently acquired. I wanted to post a few lessons learned from what I’ve recently learned on email migrations. I’ve done close to 20 acquisitions in my career, still not an expert but some may say I’m smarter than the average bear.

MigrationWiz by BitTitan

Using a migration tool is highly suggested! It’s going to cost some money but this software is worth it. In most cases if you want to migrate both email and documents it’s going to cost you around $15 per user. It’s not going to be free, but it won’t break the bank either. I’ve used MigraitonWiz for years now, there’s still my go to because of the simplicity and price.

Export Everything

I’ve worked with technical staff in most acquisitions, but very few have good backups and understanding on how everything works. Do as much exporting of properties you can to keep around for when something doesn’t work after the migration. I’ve gone to these almost every time to find an email address or forwarding rule that couldn’t remember how it worked.

DNS Updates

Be prepared and start updating DNS before the migration. I’ve been surprised to find MX records with 1 day TTLs. This doesn’t always represent how long it will take to update DNS when you are ready to cutover from one email system to another, but the shorter you can reduce these the less time you will be waiting around on migration night.

Office 365

I’ve been managing Office 365 and Exchange Online since 2015, there’s still plenty to learn for migrating. If you are doing a tenant to tenant migration, get your scripts ready! You will need to change all userPrincipalNames and Primary Email Addresses to the default domain before you can start removing email addresses. You will need to do that because you can’t remove a domain from a tenant to verify in another tenant until they are all gone. And I mean, all gone. Which brings me back to my second point, be sure you export everything first before you start deleting 😉

Last thoughts on email migrations

There’s a lot of work that goes into email migrations but the more time you spend ahead of a migration the less time it will require after you migrate. Hope these few tips will help you in your next migration. See more tips on Office 365 here.