Outlook: “Always prompt for credentials” is greyed out

If you are wondering why the “always prompt for credentials” is greyed out in later outlook versions, that’s apparently just how it is now. If you have a user that always wants to be asked for creds when opening Outlook create the following reg keys. You can also push these to all domain computers from GPO User configuration > Preferences > Windows Settings > Registry > Registry Item. Just use create and enter the key information.

Outlook 2016

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\Security

Type: Reg_Dword Name: PromptForCredentials value:1

Outlook 2013

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Outlook\Security

Type: Reg_Dword Name: PromptForCredentials value:1

Outlook 2010

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\Outlook\Security

Type: Reg_Dword Name: PromptForCredentials value:1

You have to delete the profile and recreate it after making this key, otherwise it still seems to save the password to credential manager.