Exchange 2010 email migration

We acquired a company over 200 users and they have Exchange 2010. We need to migrate their mailboxes over to our Exchange 2010/O365 hybrid. What is the best way to migrate their emails in the shortest time possible.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

carlos sotoIT AdministratorCommented:

You can do a cutover migration, a hybrid migration or just upload pst files to the cloud. See the link for more detail
migration to office 365

The fastest one is the cutover migration. Hybrid is more for long-term hybrid scenario with the local exchange and office 365. PST migratiion can take some time för 200 mailboxes but is doable if you script most of the job
CiscoAznAuthor Commented:
I think right now would be better to migrate from their Exchange 2010 to our Exchange 2010. What is the best scenario to migrate their mailboxes over to our Exchange 2010 system?
timgreen7077Exchange EngineerCommented:
do have any 2 way AD trusts because if so you can do a cross forest migtation, and if not then you will need to export their mailboxes to pst and create mailbox for those users I  tour environment and import those pst files.
Simplify Active Directory Administration

Administration of Active Directory does not have to be hard.  Too often what should be a simple task is made more difficult than it needs to be.The solution?  Hyena from SystemTools Software.  With ease-of-use as well as powerful importing and bulk updating capabilities.

Jose Gabriel Ortega CastroCEO Faru Bonon IT - EE Solution ExpertCommented:
Since your AD/Exchange/O365 hybrid infrastructure is different from the company you adquired.

you would set up a new Cross-forest migration

In this scenario is similar to the second article listed above.

You can't use a cutover migration because in your infrastructure what is "LEADING the AD" is the "ad Sync" software that pushes all the information of users from your local AD to the cloud, and keeps it up to date.

If you try to do a cutover migration you will get all the people on O365 yeah, but not in your AD, so you will have to manually create them and do a do a hardmatch of their SIDs if you do it good, if you miss a step you will lose data on the users in the process.

So what I recommend you is to set up the crossover migration from exchange 2010 to exchange 2010 and then if you want you can move them to o365 (once they're in your local AD)

Sandeep KumarAssociate ConsultantCommented:
You can simply export users with contacts, calendars and other items from Exchange to Exchange, Live Exchange and Office 365 with the help of Import / Export feature of Kernel for Exchange Server recovery software. Go through to know more about Import Export function and download the Exchange Recovery software.
Todd NelsonSystems EngineerCommented:
Check out hybrid multi-forest migrations ...

There is no need to perform a cross-forest migration.

Essentially, at a high level...

  • Configure two-way trust
  • Configure AAD Connect to sync AD object from both forests
  • Configure hybrid on Exchange 2010
  • Migrate mailboxes

Ideally, I would recommend upgrading Exchange 2010 to 2013 for hybrid multi-forest migrations but it's not necessary.

Alternately, there is BitTitan and other 3rd party migration vendors.
CodeTwo SoftwareSoftware DeveloperCommented:
I think the ideal solution would be to migrate all mailboxes to your Exchange 2010 Environment and let your Hybrid configuration do the rest.
If you are looking for the quickest way to migrate mailboxes, you might consider using CodeTwo Exchange Migration. With the help of this software, you can, for example, migrate all recent mailbox elements. Next, move all the remaining items. This will allow users to migrate to the target environment in no time.
CiscoAznAuthor Commented:
We do have a 2 way trust already and will be using ADMT and trying to find the best way to migrate users mailbox from their Exchange 2010 over to our Exchange 2010. Afterwards we can move them over to O365.
timgreen7077Exchange EngineerCommented:
See the below pdf attachment I used when I performed a cross forest migration between forest with Exchange 2010.
I would create a test account and do test run to make sure you are comfortable with it and everything is working correctly and the user attributes have been moved over. It was a smooth move once everything was in place.
Todd NelsonSystems EngineerCommented:
What is the best way to migrate their emails in the shortest time possible.

I don't feel that a cross forest migration accomplishes what you requested "in the shortest time possible" as it is a two step process to get the acquired Exchange 2010 mailboxes to EXO.  Why move them twice, when you can move them once?

Good luck.  Keep us updated.
CiscoAznAuthor Commented:
Aaron GuilmetteTechnology Solutions ProfessionalCommented:
It depends what you want the end-user experience to be, and what you want the end management state to be.

Exchange 2010 supports hybrid migration as well as multi-forest migration, so, if you plan on synchronizing identities to Office 365 (via AAD Connect), then hybrid migration is probably your best strategy.  It will provide the best end-user experience and, if you have a working OWA/CAS environment in the new environment with a valid public certificate that is exposed to the internet, should only take you about 30-60 minutes to configure.

You can re-run the AAD Connect setup in your current organization, and include the newly acquired company's forest (after configuring a trust), and most likely select the option that your users are represented by a single identity in each forest.  You'll then basically go through the same process you used to set up your original hybrid environment in the new environment:

- verify domains for new org in existing Office 365 tenant
- run hybrid configuration wizard on new org
- creation migration endpoint in Office 365 pointing to new org
- run migration batches

Once that's done, you can migrate the identity to your existing AD forest (if desired) and re-map the migrated user accounts to the existing Office 365 mailboxes.

We provide a lot of guidance around this in
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.