Domain delete and email ramifications

New Contributor

I have a question and I'm fairly sure I'm overthinking it but just want to be sure. Our company has parted ways with our umbrella company and we have to hand back our domain name at the end of the month.

If I export all of our emails and import them into my new domain's email address will they exist there even once the original email and domain they were sent to is deleted?


As a secondary question is there an easy way to export email to a .pst from an account in smaller batches to avoid the chance of an error?


Any advice appreciated.

3 Replies
best response confirmed by Dynamic_Tan1 (New Contributor)



Yes, your emails will still exist after you removing the domain, but the problem is that a mail that you export and import will still have the old domain, so if someone open a old mail to reply to in back to an colleague they will reply to the e-mail with the old domain.


Will you go to a new Office 365 or will you stay in your existing tenant? If you stay in your existing there is no need for exporting and importing via PST files.


If you moving to a new tenant I recommend that you use a third-party tool to migrate mails between tenants, with this tool you can start synchronizing today and the tool will make sure that the target mailbox is up to date until you complete the migration. These tools can also help you with changing domains during the synchronization, so it will change to and from fields in e-mail objects from to 


If you don't use third-party tools you can export with eDiscovery and do filtering with date, that will create small batches.


If you use outlook to import export I've seen that even if you export to an PST correctly there can be problems importing the PST due to corrupt items, also if the PST gets too large Outlook will crash when importing/exporting.

Thanks very much. We are staying within the same tenant.
When I look at email migration it always seems to refer to 1000’s of email addresses. What is the simplest way to transfer email within the same tennant? At the moment I’m only looking at transferring 2 addresses over.

If you are staying in the same tenant you only need to add the new domains and make sure that the address for all users are changed, you don't have to migrate or move any mails. It can be good to have both the old address and the new address assigned to user accounts for a while, but with the new address as the default email address and the old as an alias.


You can use powershell if there is many users to change domain for or you can select multiple users in the Office365 admin portal and change domain.


So do the following

  1. Add new domain in Office 365
  2. Change domain for some users (in O365 portal or Powershell)
  3. Test all functions for those users and make sure that the new domain works for you
  4. Add the new domain to all users.
  5. Communicate external and internal that you changed address.
  6. Inform some extra that you changed addresses
  7. Check if you still get mails on the old domain
  8. Inform more about the domain change
  9. Remove the old domain from your tenant and it will be removed from your user accounts.

/Linus Cansby