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.Д¬lose Outlook and open the registry editor.

You can edit the registry to remove the primary assignment, however it is not supported and not recommended by Microsoft. Remove the primary account by editing the registry

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. 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. I said it was convoluted, although it's not bad if you only have a couple of Exchange accounts. You'll need to restart Outlook one more time to remove the *.pst from your profile. Go to account settings and set the *.ost as default. Remember: the first account added to the profile is the primary account (In my experience, the new account may not be listed in until you restart Outlook.) You'll need to add a pst to the profile and set it as the default data file, then restart Outlook.Д¬lose Outlook and return to the Control Panel, Mail applet and add the new account. Go to Control Panel, Mail and remove all of the Exchange accounts from the profile, removing the primary account last. 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. 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. You have three choices when you need to remove a primary account from your profile. 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. The recommended method to change the primary account is to recreate the userвЂ™s profile and add the appropriate account first. 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).ДЄll other Exchange accounts added to a profile are considered secondary accounts.

The primary Exchange account is the first account added to the profile.

How to delete outlook account 2015