How do I report a stolen laptop to Microsoft & can it be blocked

Ok, if it is successful, that means your account was compromised, but it can be related to the laptop being stolen, or not related at all, as others can access your account from any device.

Good that you have changed your password and updated security contact info.

This Warsaw log in, is it a successful log in, or just some failed attempt?

If it is failed attempt, it is not meaningful as it means your account security measurement is effective.

If it is successful log in and not yours, it only means your account is compromised, but it doesn't mean it is from your device, it can be from any device.

No need to unlink your device. Change your password, and make sure you have two-step verification enabled and make sure all of the security contact info is up to date. https://account.live.com > Security > Manage how I sign in.

Two possibilities:

1. Device location service wasn't enabled on that laptop prior to being stolen.
2. Device is currently off and not connected to the internet. So the "lock" is staged but would kick in when connected.

Microsoft leaves the device lock feature in the hands of users because verifying device ownership is a gray area. If Microsoft were to accept lock requests directly, it could lead to complex verification processes and pose a risk of unintentionally interfering with someone else’s device.

Also worth noting, the lock feature operates at the account level only. Since Windows is just software running on the device, a thief can bypass it by performing a clean install directly from the BIOS or firmware, completely outside of Windows. Microsoft can't prevent this because most computers aren’t made by Microsoft; they’re manufactured by third parties like Dell, HP, and others. So, turning a computer into plastic paperweight is simply not possible. Sorry!!

Hello

Sorry your laptop was stolen.
Microsoft doesn't take report for stolen laptop. If you had location feature enabled prior to this on that device, you can go to https://account.live.com > Devices, find it and lock it there.
If you never enabled location feature prior to this, you might want to change your Microsoft account password.

At the same time, hopefully you have reported to local police.