Earlier when you were signed into Windows 8 with Local account, you’re required to sign-in to Mail App using Microsoft Account (that is Live ID). When you first launch Mail App while not using Microsoft Account, it’ll prompt you to Switch to Microsoft Account on this PC.

Disable Microsoft Account requirement for Windows Store apps

But with Windows 8.1, you are no longer required to do so. Enterprise Customers who use domain accounts and do not use Microsoft Accounts,will be able to use Mail App with Windows 8.1. And this applies not only to Mail App, but to other Windows Store Apps that support the feature and requires a Microsoft Account.

Let us see how to do it, for this you’ll need to Enable the following Group Policy. (You should have admin rights to run Group Policy Editor). From Start Screen, just start typing Group… & you’ll be provided with Search results.. Click on ‘Edit Group Policy’.

Allow Microsoft accounts to be optional

And from Group Policy Editor go to Computer Configuration > Administrative Templates > Windows Components > App runtime > Allow Microsoft accounts to be optional.

And Enable Allow Microsoft Account to be optional.

Once you do that and if you run the Mail App now, you’ll be prompted to use an Enterprise Account instead.

Click on ‘Show more details’ if you want to enter Server Address, Domain and Username.

To do it via the Windows Registry, navigate to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\Policies\System

and create a new DWORD MSAOptional. Set its value to 1.

This will disable the requirement of using a Microsoft Account for using any Windows Store app in Windows 8.1.