challenge phrase appears after each start

It sounds like your PC is configured to require a BitLocker recovery key or challenge phrase during startup, which can occur if the system detects a potential security issue, such as a change in the boot environment. This can happen after a shutdown, especially if there are changes to the hardware or firmware settings, or if the TPM (Trusted Platform Module) detects something unusual.

To address your concern:

1. Check BitLocker Settings: You can use the manage-bde.exe -status command to check the current BitLocker protection mode and see if there are any issues that need to be resolved.
2. Review Recent Changes: Consider if any recent updates or changes to your system might have affected the BitLocker configuration.
3. Malware Scan: It's a good idea to run a full malware scan on your system to ensure that there are no malicious programs attempting to access your PIN.
4. Resetting BitLocker: If you continue to experience this issue, you may want to reset the BitLocker protection by suspending and then resuming it, which can help clear up any persistent recovery prompts.

If the issue persists, you may want to consult with IT support or refer to the documentation on BitLocker recovery processes for further assistance.

Hi Mehrdad Ordoukhani,
Welcome to Microsoft Q&A forum. I'm happy to help.

If you turn on your laptop and instead of the usual sign-in screen you see a prompt asking for a Challenge Phrase (for example: A1B2C3) before entering your PIN or password, this is a security measure built into Windows. 

Windows shows this when it detects multiple incorrect sign-in attempts (PIN, biometric or password) and needs to verify that you’re a legitimate user.

Why you might see it

Here are common reasons:

• You- or someone else- entered the wrong PIN or password several times.
• A trusted sign-in method (PIN, Windows Hello) failed repeatedly.
• The system flagged unusual sign-in attempts, so it triggered the challenge phrase as a "captcha-style" checkpoint.
• The hardware keyboard layout changed (for example external keyboard with different layout) and the wrong characters were entered multiple times.
• Some system files related to Windows Hello / PIN were corrupted, causing repeated failures.

Normally, it should stop appearing after you don't enter anything wrong for some time. But if it's persisting, try this optional bellow.

Optional: Reset the PIN / clean up Windows Hello data

• Go to Settings > Accounts > Sign-in options > Remove PIN and Fingerprint.
• Add PIN and Fingerprint again.

I hope that above information is helpful to you.

If you have further questions, please feel free to let me know.

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