When you move from one Microsoft Exchange service to another, such as from an internal Exchange server to Office365, and want to retain the current profile, you cannot remove the original Exchange account from your profile.
The primary account cannot be removed unless it is the only account in the profile. You must remove all other Exchange accounts before removing the primary account account.
Logically, making the new email account and its data file the default should work, but changing the defaults doesn't change the primary or principal account.
Primary Exchange Account
The primary Exchange account is the first account added to the profile. The primary account cannot be removed from a profile until all other Exchange accounts are removed from the profile (when the primary is removed, the next Exchange account added is considered the primary).
All other Exchange accounts added to a profile are considered secondary accounts.
The recommended method to change the primary account is to recreate the user’s profile and add the appropriate account first. However, there are two other options: edit the registry then remove the primary Exchange account from your profile or add a pst file to the profile, set it as default then remove the Exchange accounts.
Removing the Primary Account
You have three choices when you need to remove a primary account from your profile. You can make a new profile (recommended), remove all Exchange accounts from your profile then add the new account back, or remove a key from the registry so you can delete the primary account from the registry.
While making a new profile might be faster (and is the recommended method), there is a convoluted method you can use to change the primary account and keep the profile, retaining profile-specific settings.
Go to Control Panel, Mail and remove all of the Exchange accounts from the profile, removing the primary account last. You'll need to add a pst to the profile and set it as the default data file, then restart Outlook.
Close Outlook and return to the Control Panel, Mail applet and add the new account. (In my experience, the new account may not be listed in until you restart Outlook.)
Remember: the first account added to the profile is the primary account
Restart Outlook. Go to account settings and set the *.ost as default. You'll need to restart Outlook one more time to remove the *.pst from your profile.
I said it was convoluted, although it's not bad if you only have a couple of Exchange accounts... if you have a lot of Exchange accounts or the mailboxes you are keeping in the profile are huge, you can edit the registry to remove the 'primary' flag then delete the account. Editing the registry is generally the better option when the mailboxes will take a long time to re-sync (or you are on a metered connection) or if you have a lot of Exchange accounts in your profile.
Remove the primary account by editing the registry
You can edit the registry to remove the primary assignment, however it is not supported and not recommended by Microsoft. If you mess up, you will need to make a new profile, restore the profile key you exported, or use System Restore to go back to a previous restore point.
Close Outlook and open the registry editor.
Press Windows key + R to open the Run command then type regedit in the Run field and press Enter.
Tip: Export the profile key before editing, so you can recover your profile if you make a mistake.
In Outlook 2016, the profile key is at:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Profiles\profile-name
In Outlook 2013, the profile key is at:
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Profiles\profile-name
To remove the Outlook 2010 primary account from the registry, go to the profile key:
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\Current Version\Windows Messaging SubSystem\Profile\profile-name
Export the profile key then search for and remove one (or both) of the registry keys related to primary account.
I searched the profile for 001f662b (or 001f6641 in Outlook 2016) as this value is used by each account. You'll find two keys containing this value for each account and you need to delete the second key that belongs to the primary account (you can delete both keys). Once I did this, I could delete the primary account from the profile.
To verify it's the correct account, either look at the alias in 001e660b (the alias is at the end of the data: /o=ExchangeLabs/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=74479d8714d3414c8502650cc962e1c6-maryc) or double click on other keys and look for the address. For example, in the screenshot below, the address is in 001f6641.
Note: you need to delete the entire key (on the left side), not just the registry value. The value helps you find the right key to delete.
In current versions of Outlook 2016/2019/Outlook 365 (subscription) you will not have the visual clues to identify the account. Search for 001f6641 and delete the first entry found, after verifying the key belongs to the primary account. Try removing the account from the profile (in Control Panel, Mail), if it fails, find the next key for the address and try again. (There are at least 3 keys for each Exchange account in the newer builds.)
Nobody created a free sw on github to do this old school trick ?
No, not that I'm aware of.
The registry trick worked wonders! I have a few work and business related accounts with tens of gigs of data each, so removing the Outlook accounts and adding them back later wasn't really an option. However, I had to search for "001f6641" in the Office 16.0 keys sequentially and view the binary data to see that I have the email address of the primary account that simply can't be deleted. After deleting that key, it was smooth sailing removing the mail and outlook data files.
THANK YOU!!
Is there any impact on leaving the old account? We merged with another company so there is a new O365 email account along with the original O365 account in one Outlook profile. The orignal O365 account is the primary account that can't be removed. The original O365 subscription will end in a month's time. My question is will this impact the user in any way by leaving the old account? Doesn't sound like it according to this thread, but would like to triple check.
The only issue is the user will get log in prompts - they will need to cancel the login and it will work, but it gets annoying.
The posted instructions for removing the profile in the registry key were clear, however, I did not follow them correctly. After finding and confirming a SMTP was the right profile, I only removed the key 001f6641, not the value (folder)! In going back now, I have no idea which value should be removed as I already removed the key. Outlook opens with error messages so clearly it's been corrupted. Please advise. Thanks.
It would be easier at this point to create a new profile, but you can search for 001f3001 - that key has the email address. When you find the primary account, delete the key.
The 1st method worked for me, had an old deleted 365 account stuck there, sheeeeeshhhh!
Thanks a bunch!
The registry method worked for me in Outlook 2019/365, though I found the directions confusing. To clarify them: ■ Navigate to the profile that you're modifying. It will be a subfolder with the profile name in the folder HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Profiles\ (You may only have one profile, and I believe the default name is "Outlook"). ■ Search for the indicated key value (001f6641). ■ Double click the key value found to edit it, and see if the text version on the right side of the edit window says SMTP:youremail@yourdomain.com (with periods between the letters, as seen in the image) where youremail@yourdomain.com is the email account that you are trying to delete. ■ If the text version is not SMTP:youremail@yourdomain.com, close the edit window and search again to find the next key with the 001f6641 value. Repeat this process until you find the key with the correct SMTP and email value. ■ Delete the entire key. Not the 001f6641 registry entry, but the entire folder containing it. This will be the entire folder containing the 001f6641 registry key, which will be a 32 digit alphanumeric value. ■ Restart Outlook and you should now be able to delete the previously primary email account. I… Read more »
Thank you for the instructions, that's more clear than the original post indeed! It didn't work directly for me though. I had several instances of 001f6641 linked to the email address that I wanted to delete, I deleted all of them. Outlook then refused to start, an error message prompted saying that folders were missing. I then went to Control Panel/Mails, and removed my account from the mail tab and data tab (as suggested by another comment). Outlook then successfully worked.
This is it.
Thank You so much. Like tswatek below the Exchange account took over. In my case I had 3 entries with the email I wanted to delete. I deleted all 3. Restarted Outlook and its done. Thanks Again! Clear and Effective.
No need to go into the registry files! I just figured it out. In outlook, you go to edit accounts under account settings. Under email, you must change the default email account to one that is NOT the one you're trying to remove. Then go to the next tab titled "data", you must also make sure the account you're trying to remove is NOT the primary data account. Select the new primary account. Once the data files have copied over (this will happen in the background), you can then remove the email account that was considered "primary". Much easier to do it this way and without accidentally changing a registry file and destroying your computer.
Are you using more than 1 Exchange account? Your steps work when there are not more than 1 exchange accounts in the profile.
How do I gotta remove It unknown email addresses from my mail account?
An early Outlook 2016 build was the last that I confirmed that it worked.
Oh... it worked this morning. I had to delete 3 keys that contained the primary account's address - including this one. (In a later test, deleting the first key containing the address worked. will need to update the article.)