Built-In Administrator Account Migration

[Bankesy]

Good afternoon all,

 

Currently going through migration from Exchange 2019 on prem to 365 and facing an issue with the built-in administrator account being mail enabled. I understand this account isn't synced from AD\Exchange to cloud automatically and should be mail disabled as part of removing all mailboxes from mailbox databases.

 

But it is used for e-mail, guess the real issue here is why it was ever used for e-mail but that is before my time.

 

Can't migrate it as that just produces a "A recipient wasn't found for "user@domain" on the target. Create a recipient of the appropriate type for this migration on the target and try again."

 

Gather that I cannot create a recipient as that also creates a user but wouldn't that be a duplicate user?

 

Having said that, just noticed the Administrator user doesn't show up in Admin Centre...so the answer is to create an Administrator user with administrator@ e-mail in 365 then mail disable the on-prem Administrator account?

 

Anybody else had this problem?

 

Thanks

[chaplic]

yep

 

Create new mailbox with on prem AD account

 

Add a bunch of new email addresses to ex admin mailbox

 

Look at proxyAddresses field in AD for admin mailbox, take all addresses apart from new ones

 

Paste into proxyAddresses field in AD account for new mailbox

 

export/import mail via PST if you wish.

[Bankesy]

@chaplic

 

Thanks for coming back to me, may I ask for some clarification please?

 

Create a new mailbox with on prem AD

-But still just call it Administrator? Or call it something else like " Administrator"?

-Guessing it wouldn't allow two accounts of the same name anyway so probably answered my own question there

 

Add a bunch of new e-mail addresses to ex admin mailbox?

-Just some literally made up (but sensibly named) ones?

 

As I've typed this out I think I've got the logic, essentially it's moving the existing e-mail addresses for the admin mailbox to a new account so e-mails to those addresses are still received.

 

But I should retain the primary SMTP of the mailbox I create and add in the ex admin addresses as aliases right?

 

Then punt new admin mailbox to the cloud and mail disable old admin mailbox?

 

Thanks

[chaplic]

Yes, thats it. It's only when proxyAddresses field is empty that the UPN becomes an email address (in O365). Be sure to take across any x500: and x400: addresses if present, too.

 

I dont think it makes a difference if your administrator address is primary or not, other than cosmetics.