Windows remains functional without activation, but you'll be locked out of personalization and other non-essential features until it's addressed.

While you can activate Windows through the Settings app, you also can use Command Prompt to make bulk activation easier ...

To fix Activation error 0x8004FC12 on Windows 11/10, use the FSUTIL command to clean up excess old Transactions on your PC. More suggestions here.

On Windows 11, you can check the activation status in three ways through the Settings app, Command Prompt (or PowerShell), and the Run command, and in this guide, I will teach you how.