Windows 10 not accepting PIN all of a sudden..... :(

Hi all,

Hope someone can assist....

My father's Windows 10 machine stopped accepting his PIN all of a sudden. There is no other sign-in option. I read that there's a way to get them back but since he only ever logs in with his PIN he has no idea what the password is (if any).

When clicking on forgot my PIN the email address listed is a really old one that he longer uses nor can get into. Started filling in the form to try and regain access but after Microsoft's verification it has been unsuccessful....

Is there any other way I can somehow fix it for him? Any help would be greatly appreciated.

Also why would this happen all of a sudden? He's been using the same PIN forever and it stopped working all of a sudden?

Hi, it seems the account in question uses an MS live id.

You will know that even if a PIN is used, the underlying password is the key thing and remains- and indeed in certain cases will be required and a prompt given asking for the password in normal usage.

Sadly people don't realise this, and MS fails to make this clear.

If you look carefully at the MS account verification procedure, you may be able to find a way forward:
How to Reset Your Windows Live ID and Password | Small Business - Chron.com

E.g. the alternate email address and mobile phone options, and finally the questionnaire.

4 Choose "Send a Code to My Mobile Phone" if you provided your cell phone number when you created your Windows Live ID. Enter the code that Microsoft sends to your phone via text message into the Enter Code box. Enter a new password for your Windows Live account.

5 Click the "I Can't Use Any of These Options" link if you are unable to reset your Windows Live ID password using any of these methods. Provide your Windows Live ID and alternate email address. Click "Next." Complete the questionnaire provided and wait for Microsoft customer service to respond to you via your alternate email address. This may take up to 24 hours.

You can try Option 2:
Reset Password of User Account in Windows 10

As to the loss of the PIN, note that a hash of the PIN is stored on disk:
hashing - Where is the Windows 10 PIN stored? - Super User

Potentially disk failure or corruption could lead to it not being recognised.

Check the disk and file system.
(Hard Disk Sentinel + chkdsk)

Resetting biometric data:
With the ngc file in mind:
How to Reset Windows Hello Biometrics