Hello, thank you for reaching out to Microsoft Q&A.
Open an incognito/private browsing tab in any web browser and sign in with your Microsoft account here:
https://account.microsoft.com/devices
Select the device you want to remove from your Microsoft account, and then click Remove.
If you still see the old device under Settings > Accounts > Linked devices, try the following:
Go to your Microsoft account home page online and select Security.
Or, sign in directly here: https://account.live.com/proofs/manage/additional
- Make sure all of your security information, such as your recovery email address and phone number is active and working. Then, add another new recovery email on the Manage how you sign in page. Next,
Scroll down the page and select Reset Windows Hello on all of my Windows devices.
Once you’ve done this, restart your computer and check whether the device is still visible under Linked devices in your account.