Before replacing any FRU, ensure that you have disabled the built-in battery.

For Windows 10, disable Fast Startup before disabling the built-in battery.

To disable Fast Startup for Windows 10, do the following:

1. From the desktop, type Power in the search box on the taskbar, and select Power Options.
2. Click Change what the power buttons do on the left pane.
3. Click Change settings that are currently unavailable at the top.
4. If prompted by User Account Control (UAC), click Yes.
5. Clear the Turn on fast startup check box, and then click Save changes.

To disable the built-in battery, do the following:

1. Turn off your computer and disconnect the ac power adapter and all cables from the computer.
2. Turn on your computer. When the logo screen is displayed, immediately press F1 to enter ThinkPad Setup.
3. Select Config ➙ Power. The Power submenu is displayed.
4. Select Disable built-in battery and press Enter.
5. Select Yes in the Setup Confirmation window. The built-in battery is disabled and the computer turns off
6. automatically. Wait three to five minutes to let the computer cool.