In one of the previous articles I have already described how to add Office 365 custom domain. Today’s article will be about the opposite action: how to delete a custom domain from Office365 when you no longer want to associate your account with this domain name. See the checklist below.
Before you delete a domain name from your Office 365 make sure that you have removed everything that is using this domain name.
Users’ Office 365 custom domain
Set up alternative email addresses to all the users who were under the domain you are about to delete. If you do not have any more custom domains you want to set up you may simply set it back to yourcompany.onmicrosoft.com domain.
If it was a test account you may just delete all the users.
Distribution groups
If you use Office 365 Small Business plan go to Admin -> Add users, reset passwords, and more -> Groups.
For every group select Edit and choose either a different custom domain name or yourcompany.onmicrosoft.com address.
If you use any other plan go to Admin -> Exchange -> Recipients -> Groups.
For every group that uses this domain choose Edit and change the address to yourcompany.onmicrosoft.com.
If you still cannot delete the domain the system will offer you some alternative actions, so keep your eyes open.
If you have removed the domain and then by chance need to get back all the information related with it you will easily do it if you did regular backups of your Office 365 account with Upsafe application.