Unknown default password

Start with the advanced system recovery options using method 1 from this page: Windows Advanced Recovery Options.
The principle is to restart to the page where you're prompted for the password, with the icon at the bottom right while holding the shift key.

If you cannot get to the window where Windows asks for passwords, due to a blockage or crash beforehand...
Turn off the computer twice during the Windows loading.
It will enter repair mode, which will also give access to the advanced system recovery options.
(If booting to the advanced recovery options is impossible, you need to create a USB drive to boot from; there's a link on the previous page for that).

From Troubleshoot, you can then attempt to reset Windows 10.

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Hello,

You are supposed to configure Windows upon first startup, including creating a user with a password of your choice.

Was none of this done?

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Thank you very much! It worked!!!

Great! Thank you! I'll do that tonight and I'll get back to you to let you know if it worked!

You're welcome :)

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