Administrators can prevent users from adding personal email accounts to Outlook by setting a registry key. This can be pushed out using a logon script or group policy. It can also be disabled when creating an install package using the Office customization tool (OCT).
These keys apply only to new accounts; if the user already has an Internet account in their profile, setting these keys will not disable the account.
Navigate to the Outlook\Options registry key in Windows registry. Add a DWORD value for each of the protocols you want to disable with a Value Data of 1. To enable the protocols, delete the key or change the value to 0. Once you disable POP3 and IMAP, the options to add POP and IMAP accounts will be disabled in the Account Setup dialog. In the new Simplified Account dialog, the Gmail button will not be disabled but the user will be unable to complete the account setup wizard. The DisableExchange value does not prevent users from adding Outlook.com or Office 365 Exchange accounts to a profile.
After adding the key to the registry, you may need to restart Outlook.
DisablePOP3 DisableIMAP DisableExchange DisableHTTP DisableOtherTypes
Note: HTTP protocol is no longer supported by any servers and is not an option in Outlook 2010 or newer.
Outlook 2016, 2019, 365
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options DWORD: DisablePOP3 Value: 1 DWORD: DisableIMAP Value: 1
Outlook 2013
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Options DWORD: DisablePOP3 Value: 1 DWORD: DisableIMAP Value: 1
Outlook 2010
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Options DWORD: DisablePOP3 Value: 1 DWORD: DisableIMAP Value: 1
Outlook 2007
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Options DWORD: DisablePOP3 Value: 1 DWORD: DisableIMAP Value: 1
Do it for me
If you don't want to edit the registry yourself, you can download the Registry file for your version of Outlook to set the keys. Note that all of the Disable* values are in the reg file. Open it in Notepad to edit it.
DisableAccounts 2016 DisableAccounts 2013 DisableAccounts 2010 DisableAccounts 2007
Block creation of Outlook.com MAPI accounts and PST files
In addition, you can set registry keys to prevent users from adding Outlook.com accounts to their profile and to disable the ability to create pst files.
HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\outlook DWOWD: disableexchangeconsumeraccounts Value: 1 DWORD: disablepst Value: 1
disableexchangeconsumeraccounts disablepst
Apply using Group policy
To set the values using group policy, use these registry keys:
Outlook 2016, 2019, 365
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\ Outlook\Options
Outlook 2013
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\ Outlook\Options
Outlook 2010
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\ Outlook\Options
Outlook 2007
HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\ Outlook\Options
Set the DWORD value to 1.
DisablePOP3 DisableIMAP DisableExchange DisableHTTP DisableOtherTypes
This worked well. My question is how do you revert it and reenable it if you need to? Set the registry items to 0? I did this and was unable to get the machine back to a point where I could add new outlook accounts.
Correct, changing ot 0 should work - but you will need to restart Outlook. Or you can rename the value (I add -- to the end of the name) then restart Outlook.
Is there a registry key I can search on for workstations that already have external accounts configured? We are implementing a group policy as outlined above, but that won't stop individuals who already have the IMAP accounts configured.
Look for "SMTP Server" under the profile (HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\Profiles in Outlook 2016, Outlook 2013 is the same, but 15.0) - that would cover pop3 and imap. Outlook.com (EAS or Outlook Connector) would use a different value but i'm on the road and can't check for a unique value. It would be under ...\Profiles\profile-name\9375CFF0413111d3B88A00104B2A6676 - each account or service in the profile is under that path, in a key named 0000000n where n is a number.