How to install Windows 11 on ThinkPad T420 laptop?

Trying to install Windows 11 on ThinkPad T420 blindly without understanding the hardware limits can cause issues. If you ignore the fact that your T420 lacks TPM 2.0 and Secure Boot, the installer might refuse to continue or cause problems later on. To avoid this, make sure you’re prepared to bypass these checks safely. Changing BIOS settings incorrectly can brick your laptop or make it unbootable. For example, disabling Secure Boot without understanding it, or messing with UEFI/Legacy modes, can cause boot issues. Double-check your BIOS options and save only the changes you understand.

If you skip disabling Secure Boot or forget to enable Compatibility Support Module (CSM), your USB boot might not work, or the installer won’t start. Make sure you do this step right before booting from the USB. Using the wrong tools or files to create your install media can lead to corrupt or unbootable USB drives. Use reliable tools like Rufus or Media Creation Tool, and ensure you select the right options.

After installing Windows 11 on ThinkPad t420, some hardware might not work properly because drivers are missing or incompatible. Don’t just install and forget — be ready to hunt down drivers for Wi-Fi, graphics, etc., especially since your hardware is old. Even though the T420 can run Windows 11 with 4GB RAM and 64GB storage, it’s tight. If your hardware is below those specs, the install might hang or be painfully slow. Better to check your hardware first.