Are you encountering the same issue as others: Windows 10/Windows 11 keeps asking for A1B2C3 on the login screen although you have entered the correct PIN? In this post on MiniTool, we will explore how to remove Windows A1B2C3 challenge phrase via some fixes.

Continuous Prompt Asking to Enter A1B2C3

When booting your PC to its login screen, you need to enter a PIN to sign in to the operating system. However, sometimes Windows 10/Windows 11 keeps asking for A1B2C3 challenge phrase. To be specific, on the computer screen, you see the error message:

“You’ve entered an incorrect PIN several times.

To try again, enter A1B2C3 below.”

This issue could happen although you type a correct PIN. The challenge phrase refers to a security measure to protect the system against brute-force attacks. If someone attempts to log into your account remotely, it is required to enter the challenge phrase.

In terms of Windows 11 security, besides using a PIN to protect your PC, you can also take some other measures to keep it safe, including running Windows Security, keeping Windows up-to-date, using TPM/ UEFI Secure Boot, backing up your PC with MiniTool ShadowMaker to avoid data loss, etc.

MiniTool ShadowMaker TrialClick to Download100%Clean & Safe

Then, how to remove Windows A1B2C3 challenge phrase to successfully log into the system? Let’s delve into some available workarounds.

Fixed - Something Happened and Your PIN Isn’t Available Win11/10
Fixed - Something Happened and Your PIN Isn’t Available Win11/10

What should you do if you get the error saying something happened and your PIN isn’t available in Windows 11/10? Find out solutions here.

Read More

Way 1. Enter Challenge Phrase or Use Other Sign-in Options

While Windows 10/Windows 11 keeps asking for A1B2C3 on the login screen, you can enter A1B2C3 and then the PIN/biometric information. Alternatively, click Sign-in options to choose another option for Windows login if you ever configured other methods like a password.

Way 2. Delete the Ngc Folder

Windows stores your login information in the Ngc folder. Due to some reason, this folder could go wrong and get damaged. Needless to say, some login errors happen. If Windows keeps asking to enter A1B2C3, try to delete the Ngc folder via the steps below.

Step 1: Press Win + E to open File Explorer.

Step 2: Unhide AppData by clicking View > Show > Hidden items in Windows 11. Then, access this path: C:\Windows\ServiceProfiles\LocalService\AppData\Local\Microsoft.

Step 3: Right-click on the Ngc folder and choose Properties.

Step 4: Under the Security tab, click Advanced.

Step 5: Tap on Change, type administrator in the text field, and click Check Names > OK. Apply the change by Apply > OK.

Step 6: Choose the Ngc folder and click Delete.

delete Ngc folder

Way 3. Reset Access Control Lists

Usually, if the access control lists (ACLs) in the Ngc folder turn corrupted, Windows 11 keeps asking for A1B2C3 challenge phrase. To fix this issue, you can reset ACLs.

Step 1: Open Command Prompt with admin privileges.

Step 2: Copy and paste icacls C:\Windows\ServiceProfiles\LocalService\AppData\Local\Microsoft\Ngc /T /Q /C /RESET to the CMD window and press Enter.

Step 3: After the reset, you can add a new PIN.

Way 4. Create a New PIN

Your old PIN may have something wrong, most likely the sign-in data is deleted, as a result, the A1B2C3 challenge phrase always appears. You can try to create a new PIN to solve your issue.

Step 1: Access the Settings app via the Win + I keys.

Step 2: Navigate to Accounts > Sign-in options.

Step 3: Expand PIN (Windows Hello), click Change PIN, enter your old PIN, and type in a new PIN.

change PIN Windows 11

Step 4: Restart your PC and log in to Windows using the new PIN. Then, the continuous prompt asking to enter A1B2C3 won’t appear.


How to remove Windows A1B2C3 challenge phrase? If Windows 10/11 keeps asking for A1B2C3 on the login screen, try the solutions above to easily address this issue.

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