Last reviewed on May 14, 2015   —  52 Comments

Applies to: Microsoft Outlook 2010 and up configured with Microsoft Exchange Server accounts

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 it's data file the default should work, but changing the defaults doesn't change the primary or principal account.
Primary account warning dialog

Primary Exchange Account

The primary Exchange account is determined by 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.

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

In Outlook 2013, the profile key moved to:

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 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.

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.

Remove a key from the registry to delete the primary account

Discuss in our community


  1. Michael says

    In the text you say you searched for 001e660b but the screenshot shows 001f662b.
    Which one should i remove?

    • Diane Poremsky says

      Thanks for catching that. I meant to say to verify the key belongs to the primary account by looking at the 001e660b value. Delete the entire key on the left side, not the values.

  2. Jimmy McDaniel says

    Have you experienced an issue where it will let you remove the primary account but then Outlook will hang when you launch it? I've successfully removed it from one machine but a few others I've tested have not gone so well. I've also discovered that one machine has 6 entries for the primary account. Deleting the second wouldn't let me remove it. I could after deleting all keys but Outlook would still hang.

    • Diane Poremsky says

      All of my tests worked fine, but I only had the two keys. This could be why Microsoft didn't publish this as an option. If deleting the key doesn't work as expected, you should use one of their recommended methods - delete all accounts or make a new profile.

  3. Jimmy McDaniel says

    Oh, and in this last case with the 6 registry keys, it doesn't allow me to delete it until I delete the last key. Still hangs Outlook thought.

  4. Stephen says

    Take big stick, hit oneself round head.

    If one doesn't administer Outlook/Exchange DON'T follow the bouncing ball. I just did and now my .ost is "configured for a different mailbox" so I can't reference it - PERIOD!

    Hosed, royally.

    Should have made a PST first - didn't know that!

    Trying to "Repair" but I have NO confidence I'll get my 481MB and nearly 2 years of emails et al back...


    • Diane Poremsky says

      Do you have system restore enabled? If so, roll back before you edited the registry. Or, if you exported the registry as a backup, you could restore it.

  5. Alan says

    I highly do not recommend following these instructions to delete the registry key unless further testing confirms it actually works. I attempted this and corrupted Outlook.

    After removing the key which contained 001f662b and 001e660b for the primary account, I was able to successfully remove the unwanted Exchange account from the Control Panel > Mail window.

    I then opened Outlook successfully and thought I was in good shape. However, when I attempted to attach/import a .PST file to Outlook either via 'File > Open > Import' or 'File > Open > Open Outlook Data File', Outlook locked up. I had to kill Outlook at that point.

    To resolve the issue that I created, I restored the registry from the exported backup that the instructions recommend you create. After restoring the registry, I am able to attach .PST files as expected in Outlook.

    Thank gosh for the back up. Again - Avoid this method! It needs more testing and/or, if I did not follow the instructions correctly, the instrustions need to be re-written more clearly.

    • Diane Poremsky says

      There is always a possibility of messing up, that is why I recommend exporting the registry.

    • Andrew Esh says

      You weren't supposed to delete the 001e660b key, just read it to see if this is the primary account. If it's one of the other accounts, don't delete any keys from it. If it is the primary account, delete only the 001f662b key from it.

  6. sori says

    If Outllok is staling or hanging after you complete the "edit registry"-method.... Use ccleaner (or another reg-fixer I pressume) to fix and cleanout registry.

    This worked for me.

  7. Stanford says

    I just tried the above method but rather than deleting *every* key which contained the value "001f662b", read the STRING VALUES in the same key (eg the value for 001e660c and 001e6614).. this is in a human-readable format and should tell you enough about which exchange server that key relates to... only delete the keys related to the Email acccount you're trying to remove...

    I can confirm this method works to remove my old Exchange account and I'm still able to attach/import PSTs in Outlook 2010 afterwards.

    And as usual with IT Admin 101: before making any changes, backup, backup and make a backup of the backups!! :) .. this will save your skin 99.9% of the time...

    Thanks heaps Diane, awesome tip!

    • Diane Poremsky says

      Correct, you only want to remove the key for the account your want to remove - if you delete it for all accounts, you'll mess up the profile.

  8. Ian says

    Worked like a charm, thanks very much! (Looking at the other values as Stanford suggested also helped to delete only the key I wanted to remove)

  9. paulbself says

    I am not looking to remove the primary account, just change it. Is it possible to just change the Primary account? Really not excited about any of the processes discussed above.

    • Diane Poremsky says

      The only way to change the actual "primary" account is by removing the current primary account or removing all accounts - the first Exchange account added to the profile is the primary. You can't change the primary otherwise. You can set a different account as default - this is independent of the "primary" account.

  10. jronquillo says

    Hi is it possible if I just need to rename the Recipients/cn= if I wanted to make the other mailbox as the default. issue on my side is I have 2 mailbox configured. mailbox A is set as default and what is happening is everytime mailbox A creates a calendar invitation Mailbox B becomes the default mail sender whilist there is no dropdown list to choose

    • Diane Poremsky says

      Are you viewing Mailbox A's folders when you create the invitation? If so, it should use the correct account provided Mailbox A is listed as an account in File, Account Settings.

  11. Antoinette says

    How would I delete an account from a standard desktop that's not on an Exchange server? What would be the filepath? I don't think it includes Windows NT. Thanks

    • Diane Poremsky says

      This only applies to exchange accounts - for non-exchange accounts, you can remove the account from File, Account Settings. Select it and Delete. Or, with outlook closed, open control panel, search for mail and edit the profile. See Add and Remove accounts for the steps.

  12. UniAdmin says

    I tried the reg key option and found several references to the old/primary mail account.
    It didn't work despite deleting all of them.

    So I tried using the option creating a new profile (in control panel - Mail 32) for the mail account that I wanted to keep, then simply adding in a new duplicate account as if starting from scratch.

    The key then is NOT to delete the OLD profile until the new duplicate account has synced up with Exchange.Once done,check your mailbox/contacts/calenders etc. to make sure all is up to date. You can then delete the other/old profile in outlook thus removing the OLD default account. I didnt need to re-import a .PST/OST as the exchange with the account I wanted to keep just updated the same EMAIL account in the other profile.

    Hope that helps

  13. Mahesh says

    i removed primary account successfully using above method. but after that i cant send email through other exchange accounts also "operation failed"..
    any suggestions...?

    • Diane Poremsky says

      There is a reason why Microsoft doesn't publish this solution and recommends a new profile. :) It has worked well for me though. So check the default settings for the email account and data file - try setting a different account (and data file) as default then back to the one you want to be default.

  14. Mahesh says

    Finally it worked for me also... i restored registry backup and tested two three times... finally it worked.... thank you very much for you valuable post....

  15. The Ninja says

    This method worked for me on one of two computers I tested it on. Both were running Outlook 2010 and both had more than one key they appeared to correspond with the primary account. In both tests, I deleted all keys except those that corresponded with the new account. The first computer did fine but the second resulted in a broken profile and an Outlook that refused to open. Oh well, it was worth a try. Infuriating "non bugs" like this is one of the many reasons I don't recommend Outlook to most of my clients.

  16. Happy Customer says

    Thank you so much for this! You saved my sanity. After getting the run around from my company's tech support for weeks, I found your instructions, followed them, and they worked. Now, my new email is the only one in my Outlook, and I don't have to worry about duplicate meeting notifications.

  17. Mark says

    This worked wonderfully for me.

    I had two account. I set the one I wanted to keep to default, and set its data file to default as well. Closed and restarted Outlook and closed again.

    Backed up the all messaging registry key just in case.

    Removed all the profiles (about six of them- maybe the multiple mailboxes within that account?) which mentioned the account I wanted to delete. Restarted the Mail applet from the control panel, deleted the old primary account.

    Outlook opened up but stalled on connecting...tried not to panic. Closed outlook (it wasn't responding) and went back to the applet and ran repair. It took about 30 seconds and then said all was good. I reopened Outlook and all is well now.

    I don't have multiple accounts now - so I can't test the cross account functionality.

    Hope this helps someone as much as it did me!

  18. David Skrabal says

    Thanks Diane. Removing that the old Exchange account from the Registry without having to remove the new one was exactly what I was looking for. Had to to clean up some other traces from the Mail control panel, but it promoted the new Exchange account to primary. Thank you!

  19. Bo says

    HM - I run Windows 8.1 and Outlook 2012.. There is no HKEY_CURRENT_USER\Software\Microsoft\Windows NT\Current Version\Windows Messaging SubSystem only ...\SessionDefaultDevices. Did anyone do it on this type of configuration. Btw. my primary account, that I wnat to delete, is an online account only. No cache.

    • Diane Poremsky says

      In Outlook 2013, the profile is under the Office key. HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Profiles
      Whether the exchange account is online or cached, the first one added is the primary.

  20. Agence Immobilière Bruxelles says

    work fine for me!
    Deleted the key, run office 2010 French version and now it's running fine !

  21. Roti says

    aaaaaaahhhh!!!!! i do this and now i cannot use my computer all it do is make the grinding noise! please advise!!!

    • Diane Poremsky says

      If you edited the registry to remove the primary account and it's not working correctly, you'll need to make a new profile. That's the way Microsoft recommends removing the primary account.

  22. Vernon says

    Using Outlook 2010. I only have two accounts to deal with, so unable to generalize to cases with more than two accounts. Also, I am upgrading from exchange to o365 using the same email address and need to retain old email.

    1. Follow your provider's instructions for creating new account and add new account to outlook. Note: My provider allows both old and new email accounts to operate simultaneously for up to 48 hours even though they use the same email address..

    2. Export old email folders to disk.
    3. Import old email folders into new account.
    4. Delete both accounts.
    5. Add new account back into outlook.

    New account will become primary and old email will be retained. Delete and add back is fast. Advantage is no registry hacks and do not have to recreate old p

    • Diane Poremsky says

      your situation is different from those who want to remove an exchange account from their profile - in many cases, they are keeping the other accounts in their profile and don't want to add them back to the profile.

      fwiw, i would probably use drag and drag to move mail, etc between an old and new account rather than export & import. you definitely want to move meetings, not export & import them.

  23. mathew says

    There is a better way to do this without editing the registry.
    1. Open Control Panel and launch the Mail/Mail (32-bit) applet
    2. Designate another email account as the Default
    3. Designate another data file as the Default
    4. Close the applet
    5. Launch Outlook
    6. Close Outlook
    7. Open Control Panel and launch the Mail/Mail (32-bit) applet
    8. Remove the email account.

    • Diane Poremsky says

      It depends on the type of email account - when you use an Exchange account, you need to edit the registry in order to delete the first account added to the profile. There is no way around it. For IMAP accounts, you can delete the first account as long as there is a different data file set as default, as removing IMAP (or also removes the data file.

  24. Rae says

    Thanks for this. I was about to delete all of the Exchange accounts until I bumped into this one. Managed to delete the Primary account without any hassle and saved me tons of time updating a 5Gb+ file size of OST, per account! LOL

    To those having a difficulty tracking THE Primary account, check with the registry value //001e660b// if it is actually THE Primary account you are looking for. If you double-click this registry value, it should open up a window which has the data of the account, its last line should consist of the name of the account you are trying to delete (ex. .../cn=Recipients/cn="PRIMARY ACCOUNT NAME").

    Make sure you backup (export) first before attempting this method. Just to be sure.

  25. Brent McDonald says

    Thank you so much for posting this. I'm running Office365 on a Surface Pro 3 running windows 8.1. Editing the Registry scares the boo-boo geebies out of me, but I backed up and proceeded as directed. It worked perfectly!!!!! No problems at all. Again, I'm grateful!

  26. Geordon says

    I successfully edited the Registry to remove my primary account in Outlook 2010. In my case, I had 3 keys for each of the accounts. I had to remove all 3 for the primary before I was allowed to Remove the account using the Mail Control Panel applet. Restarted Outlook, and everything came up smooth. Thanks so much.

  27. janjaf says

    Worked brilliantly. Made backups, and doublechecked every step, but no problems. And solved an annoying mess left behind by my wokplaces IT-department.

  28. Daniel B says

    "You weren't supposed to delete the 001e660b key, just read it to see if this is the primary account. If it's one of the other accounts, don't delete any keys from it. If it is the primary account, delete only the 001f662b key from it"

    Thanks for that addendum, this was NOT clear from the article. Glad I read the comments. Of course, it STILL won't let me delete the account and it still says its the primary acct. Typical MS.

    "There is a reason why Microsoft doesn't publish this solution and recommends a new profile. "

    Yes and the reason is they are idiots. For people with many emails in one profile, removing the entire profile and recreating it is needlessly long and complex when all they SHOULD be able to do it do delete the one email account. It's utterly unacceptable that Microsoft thinks this should be normal.

    "Infuriating "non bugs" like this is one of the many reasons I don't recommend Outlook to most of my clients"

    Exactly - it's a known issue, clearly a problem for many users, and yet MS thinks it's working as intended. I NEVER recommend outlook personally, it's just an awful awful program.

  29. Nathan says

    And this is a perfect demonstration of why microsoft sucks. I should just be able to remove the account and delete the data. IT'S MY DATA. I SHOULD BE ABLE TO REMOVE IT EASILY.

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