Impacts of changing default domain in Office 365 tenancy?

Iron Contributor

A client of mine has decided to change their company name and default email domain, an I have a few questions about what this impacts.

  1. Can I simply add the new domain to my current Office365 tenancy, or do I have to stand up a whole new Office 365 tenant, specifically for the new domain?
  2. If I can just add the new domain to my current tenancy, how would I configure Office 365 to have each user log in with their new credentials (i.e. vs
  3. Will Outlook automatically reconfigure itself for the new email domain?
  4. Do users’ local OneDrive folder get renamed to “OneDrive – New Company Name”?  If not, what would need to be done for OneDrive to reflect the new company name?
  5. Do OneNote Notebooks get renamed to the new domain name, and will the local clients reflect this?
21 Replies
My two cents here:
1. You can add as many domains as you want/need in Office 365, but just remember that adding a new domain does not imply the default onmicrosoft domain is going to change, it remains the the name change cannot be reflected in Office 365
2. You can add the new domain and easily add to every user in the tenant so the can log in using the new domain.
3. Yes
4. No, the OneDrive folder will stay with the original name.
5. No.

In addition to the accurate answers from @Juan Carlos González Martín, you should know that MS is working a tenant renaming process for this scenario. One of my customers has received some preliminary information about the program. As you can imagine, there are a lot of potential issues, your questions 4 and 5 are just the beginning. I have no idea when this will become widely available, but I would guess that it will be sometime this year.

@Deletedmay be able to provide some more details.

Adding my input here.
1. This one is in conjunction to Dean's response, the actual domain URL used for onedrive/sharepoint cannot be changed currently. You can add as many e-mail domains as you wish, you can even change your primary domain via exchange policy so it auto updates the e-mail where it comes from. Making the domain primary may even do that as well, I do it via Exchange thou because Hybrid, so depends on if your hybrid or not how that goes.

2. you can add new domain and make it primary. However you will have to run a script to change everyone's UPN logins. Something like Set-MsolUserPrincipalName -NewUserPrincipalName -UserPrincipalName

3. Yes

4. OneDrive will not change existing folder, however, new setups going forward will use the new Organization name if you change it. And if you remove and readd onedrive the default will update to OneDrive - Orgname

5. Nope, and If your talking about the URL to the notebook, see number 1. Maybe someday but right now not possible to change that URL.

Do I have to use a script to change everyone's UPN login, even if I'm using 100% cloud hosted Office 365 (i.e. non-hybrid)?   Or if when I make the new domain the default, will that automatically trigger all Office 365 users' UPN logins to use the new domain credentials?

Not 100% sure, never had a 100% Cloud tenant to mess with. You'll find out after changing it quickly if you'll need it or not :). Because when you change it via on-prem you have to use the script I would suspect you have to change it using the script on cloud only as well.
You can also change the domain for all the users in bulk using the bulk edit options in the users list in the Admin Portal...of course, this approach changes the domain, not the UPN...if you need to change also the UPN then you have to use PowerShell, but the process is quite straightforward
Changing the default will only change the UPN for new users created in future - you will need to change the UPN for your existing users, as others have mentioned.

Hi Robert,

Just curious on what happened.

100% cloud e-mail client changed company name and domain. Client wants e-mail coming from new domain.

I went to change in Admin screen and was told it would change everybody's log in. Decided to wait so I could plan for all phone and tablet changes for users.

One week later went in and now Admin center lets me change individually. (Better for me honestly, do not want to have everybody set their e-mail up again.)

I did a test and user stayed connected through Outlook from old domain.

So, did you have to remove Outlook account and just redo it?

I figured this would be the procedure on phones but not sure about desktop.

If you can, let me know what happened.



Hi Victor,


Yes, what you can do is stage the new domain and make it the default.  That will ONLY affect new users that get created after you make the new domain you default.   You will then want to add each user's new email address to their Office 365 account, but don't immediately make it their default.


You can then do individual user cut overs, by making the new email address the user's default Office 365 login.   Note that this will immediately change their login credentials so you need to let the user know that their Office 365 login is going to be changing to the new email address.


I was hoping that Outlook would 'auto-configure' with the new credentials, but found that it's easier to just create a new profile in Outlook and use the user's new Office 365 credentials.  Then let that sync up, and then get rid of the old Outlook profile.  


You should do the same for each user's OneDrive, if you use that for cloud storage, as well.

This way you can do a controlled cut over throughout your environment, rather than a single "everyone is now on the new domain" cut over which requires more hands and is a greater interruption.

Thanks for the add @Dean_Gross - yes, we've looked into this extensively for six+ months.


I've been focusing on the impacts to SharePoint/OneDrive, while others in my IT department are focusing on AD/Exchange/Skype.


My first suggestion: contact Microsoft support.  Microsoft has a process that they are currently refining to allow a tenant to change names.  Most organizations will find changing the tenant name to be disruptive, especially large and change sensitive cultures like my company - so don't underestimate the effort.


In fact, changing the SharePoint/OneDrive URLs was too disruptive for us, so we're going to wait until next year to see if Microsoft has a better process.


In the meantime, we've added our new domain as our primary SMTP address, but left the UPN and SIP set to the old address.  This can be confusing to users because almost all login prompts ask them to enter their "email address" when the prompt is actually for their UPN.  We haven't had but a few calls about this since we added the email addresses a few months ago.


We're currently testing the UPN change, which will change the URL of the user's OneDrive site (among other things).  Changing that address will break things like:

  1. OneNote notebooks that are open in the OneNote desktop app - users will need to notice that their notebooks are no longer syncing.
  2. Office recently used documents list - the links to recently used documents that are stored in OneDrive will break, because the links will continue to point to the old address.  Our testing shows that this isn't 100% of the time, but we haven't tracked down why some users are reporting that their links continue to work.
  3. Office Pro Plus login issues - I don't have the details here, but some of our people have had trouble with the Office apps not being able to login (if I remember correctly)
  4. Bookmarks/favorites/etc. - any links that someone saves, including the sharing emails they receive, will no longer work.  The permissions are left untouched, but the link in the original sharing email will no longer work.

One of the good things is the OneDrive desktop app - it will "heal" itself after a logout/reboot and doesn't require the user to do anything.


We've decided to proceed with the UPN change because we need to minimize the amount of time that our UPNs don't match what our users consider to be their email addresses.  Plus, changing the OneDrive sites won't be as bad as SharePoint because most of our sharing/active documents are in SharePoint.  Lastly - we can implement the UPN change over time, giving our help desk more time to deal with issues.  When we do the full name change, including changing the base address for SharePoint Online and OneDrive, we'll have to do that in one step and incur a high call volume for help desk.

@DeletedWe are looking at similar options with our domains.   Have you encountered 3rd party utilities that would assist in migrating tenant to tenant?

After my post in August, we found more issues with changing the UPNs for existing user accounts.  Given the amount of pain this would have inflicted on our end users, the decision was made to wait for Microsoft to come up with a better process for renaming the tenant/UPNs.


I haven't looked into 3rd party options.

Hi Kelly, Have you done any more with this process, we are about to rebrand our company and worried about the exact same issues.

Hi @dickiebird - No, we're still waiting for a more user friendly process from Microsoft.


However, Microsoft announced the ability to easily change a SharePoint site collection's URL, including redirects (look at this post for the "site rename" info), which is a very good sign.

Hi @Deleted 

Any updated information on this by any chance?

Thanks so much for your contribution here!

Hi @Maridee26  - No update, but that's because our IT department has been working on other projects and we haven't gone back to Microsoft for an update.


That said, our local Microsoft team has not reached out with any updates either, so I suspect that whatever they are working on isn't finished yet.

@Deleted just wanted to say thanks for the info in this thread :)

I'm looking to rebrand also, but as a small/new setup we can do it without major trauma

I have switched the default domain to the new brand. I'm now looking to see how to get the new default domain showing on Sharepoint, OneDrive/Windows sync folders, etc.


Yes, what you can do is stage the new domain and make it the default. That will ONLY affect new users that get created after you make the new domain you default. You will then want to add each user's new email address to their Office 365 account, but don't immediately make it their default.

We have done the domain change successfully, all our users are using new domain on all applications. The only problem I am facing is that we are unableto retrive old domain mail boxes sync to 100%.


Inbox does not show previous mails wheras sent items are showing all mails.


Can you help me on this?