Microsoft account is allowed to add or create in Windows 10/8 by default. If you want to limit the use of Microsoft account in your computer, such as disabling Microsoft logon option, you would have to block or disable Microsoft account manually. So that you will not be able to login Windows with Microsoft account, cannot add a Microsoft account, or switch a local account to a Microsoft account, or connect a domain account to a Microsoft account.
Now please follow 2 ways below to block or disable Microsoft account in Windows 10 if you need to make users unable to add or login Windows 10/8 with Microsoft account.
Step 1: Open Group Policy Editor.
Type edit group policy in Start menu or taskbar search box and then press Enter key to open Local Group Policy Editor. Or you can also type gpedit.msc in the search or Run command box and then press Enter key to open the Group Policy Editor.
Step 2: Navigate to following policy location.
Computer Configuration > Windows Settings > Security Settings > Local Polices > Security Options
Tips: Another way to navigate to "Account: Block Microsoft accounts"
1. Press Win + R to open Run dialog, type secpol.msc and click on OK. If prompted by UAC, then click on Yes.
2. In the left pane, tap on to expand Local Policies and open Security Options.
3. In the right pane of Security Options, you can see "Accounts: Block Microsoft accounts".
Step 3: Open properties of "Accounts: Block Microsoft accounts".
On the right-side, locate the entry named "Accounts: Block Microsoft accounts" and then double-click on it to open its properties.
Step 4: Select an option to block or disable Microsoft account.
Under Local Security Setting tab, click on the drop-down box and you can see the following three options:
After selecting the right policy, click Apply and OK. Sign out and restart PC to make the policy effect.
If you cannot block Microsoft account by group policy because of some reasons, please open Registry Editor and you could find Microsoft account would be also blocked or disabled with two tricks.
Step 1: Open Registry Editor.
Press Win + R key to open the Run box. Type "regedit" and hit Enter.
Step 2: Navigate to following location in Registry Editor.
Step 3: Change "NoConnectedUser" value to 1 or 3.
1. In the right pane in Registry Editor, you would see a value named NoConnectedUser.
If the value doesn't exist, right-click on the empty space to create a DWORD value and name it "NoConnectedUser".
2. Set the NoConnectedUser value to "1" if you just want to block users from switching to Microsoft account. Or set it to "3" if you want to block users from either adding or logging on with Microsoft account.
0 = Allow Microsoft Accounts
1 = Users can't add Microsoft Accounts
3 = Users can't add or log on with Microsoft accounts
3. Then you can close the Registry Editor window and reboot the PC.
Here is another trick that you can block users from switching to Microsoft account in Registry Editor. Please follow the steps.
Step 1: Open Registry Editor and navigate to following keys.
Step 2: Change "AllowYourAccount" value to 0.
In the right pane, double-click on the entry "value" and set it to 0.
Step 3: Restart your PC to make Microsoft account login disabled.
Log off and log in again your Windows 10/8 PC. Open the Settings charm and select Accounts, you'll find the option "Sign in with a Microsoft account instead" is now greyed out and disabled.
Tips: The settings to block or disable Microsoft account above will help to prevent a security hole from malicious use by people who has administrative privileges in Windows 10. But while you want to log into Windows 10 with Microsoft account later, you would need to allow Microsoft account manually in Windows 10 again just like you block Microsoft account.