Hello, Edward Kamal.
Thanks for your reply.
Have you tried creating a new account?
Create a new local account and then test in the new local account.
(Refer to this document to complete the operation.)
After testing, if the PIN can be set normally, copy the data from the old account to the new account and then use only the new account.
If the PIN does not affect your normal use, you do not need to take any action.
Here are some personal suggestions of mine.
I suggest you regularly back up important data. When you encounter some new problems that cannot be well resolved, you may choose to reinstall Windows.
Usually, reinstalling Windows can solve the new problems you encounter as well as the current PIN issue.
Disclaimer: If one day you need to reinstall Windows, please back up important data in advance.
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I will be waiting here for your next reply.
Best regards.
Malygos - MSFT | Microsoft Community Support Specialist