Kat-1329 avatar image
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Kat-1329 asked Kat-1329 published

Exchange admin center: Migrate from Google Workspace; Mail User, Create contact failed (The email address is already being used.)


Am following "Perform a Google Workspace (formerly G Suite) migration" instructions and am now at the step "Provision users in Microsoft 365 or Office 365".

Am attempting to create Mail Users, in order to add the external email address "" to my active users, as well as the proxy/alias email address "", as described in the instructions to the normal email address "".

Am getting the "Create contact failed" with "Error: The email address is already being used. Please choose another email address." I am assuming that is because there are active users with normal email address "" (with Microsoft 365 Business Standard license).

  • How can I add the required email addresses, to my active users, please, so I can continue with the migration process?

  • Does the process work with active users? Are Mail Users different from Active Users?

  • Would I need any special rights to add these two additional email addresses to my active users?

Any input would be greatly appreciated. My company really wants to move away from Google and over to Microsoft, but of course would like to migrate their existing emails.

Kind Regards!

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Kat-1329 avatar image
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Kat-1329 answered Kat-1329 published


Was able to activate the migration for all the existing users and all mailboxes are synced now.

Following "Perform a Google Workspace (formerly G Suite) migration" selectively and activating the migration part worked. However, I did not make use of either subdomain 'gsuite' or 'o365', since I was unable to add any of these to the active users that were already present and had user mailboxes. Furthermore, I did not migrate a "copy" and I did not attempt to merge mail folders, in particular, because these "copy accounts" would have exceeded our licences.

Thank you very much for your support and input! It definitely helps a lot to have someone with knowledge to write to, it is especially helpful in making sense of the system.

Unsure how to combine my comments to a cohesive description of the situation I encountered, so others may get some value from this also? Is it possible to accept your answer and point to the comment section too?

Best wishes!

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EricYin-MSFT avatar image
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EricYin-MSFT answered Kat-1329 commented

Can you post the result of the following command:

 get-recipient|fl *addre*

In my test, an exisiting user with would not cause a error, how did you create the mail user? EAC or powershell? Can you post the snapshot of error info?
Besides, why do you already have user with If the migration success and during the step mailuser converted to user mailbox, you would get same error because there is an existing

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Thank you for your response. The result of the command: See my second reply below [Edit].
Typing the command without the filter shows Name and RecipientType, where the RecipientType is listed as UserMailbox. The active users were already present in the system before I was tasked to perform the migration process for these users.

I used EAC in a browser interface, cf. snapshoot of the error info: 69116-screenshot-from-2021-02-17-12-06-03.png I've installed powershell now also, if need be.

Your remark "... during the step mailuser converted to user mailbox ..." is interesting: Is there a way of merging existing active users with migrated accounts? My thinking is to perform the migration with using other addresses first. Then, after the migration, perhaps, one could perform a merge of the respective user mailboxes (the existing with the migrated), if possible?

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It could be feasible that performing the migration with using other addresses first, you can do a test with one of the mailboxes.
To perge two mailboxes, three ways:
1. Using Search-Mailbox, but you would lose the folder structure, for detailed command see here:
2. Export it to PST file, and import the file to new mailbox :
3. Using EWS script, the script on official site is not accessible, not sure if this works:

Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

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The result of the command is as follows (real emails replaced with placeholders):

 EmailAddresses                : {SPO:SPO_11111111-2222-3333-4444-abcdefghijkl@SPO_55555555-6666-7777-8888-mnopqrstuvwxy, 
     ExternalEmailAddress          : 
     HiddenFromAddressListsEnabled : False
     EmailAddressPolicyEnabled     : False
     PrimarySmtpAddress            :
     AddressListMembership         : {\Mailboxes(VLV), \All Mailboxes(VLV), \All Recipients(VLV), \Default Global Address List…}
     AddressBookPolicy             :

Good to see an ExternalEmailAddress field. How would I access this, please, and how would I be able to add an alias also, please? Thank you for your help with this.

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This should be user mailbox type, not the mailuser type. You can run "get-recipient|fl type" to confirm it.
Editing these data would not make a sense.

1 Vote 1 ·