Lenovo ThinkPad Error 0271 — Real-Time Clock Failure

What Does This Error Mean?

Error 0271 means the CMOS (real-time clock) battery has died and the system clock cannot retain settings. Replace the small CR2032 coin cell battery on the motherboard to fix it permanently.

Affected Models

Lenovo ThinkPad T Series
Lenovo ThinkPad X Series
Lenovo ThinkPad L Series
Lenovo ThinkPad E Series
Lenovo IdeaPad

Common Causes

Drained CMOS coin-cell battery (most common — the battery lasts 5–10 years)
Loose or disconnected CMOS battery cable
Faulty motherboard CMOS circuit (rare)
Date and time settings lost after the battery died

How to Fix It

Boot into BIOS and set the date and time.

Tap F1 at boot to enter BIOS. Set the correct date and time, save, and exit. This clears Error 0271 temporarily — but the error will return next time the laptop is fully powered off if the CMOS battery is dead.
Identify your CMOS battery type.

Most ThinkPads use a CR2032 lithium coin cell wired to a small connector on the motherboard. Check Lenovo's hardware maintenance manual for your specific model.
Replace the CMOS battery.

Power off, unplug, and remove the bottom panel. Disconnect the small CMOS battery cable from the motherboard, replace the cell with a fresh CR2032, reconnect, and reassemble.
Reset BIOS date and time again.

After replacing the battery, the BIOS will be at default settings. Enter BIOS (F1 at boot), set date and time, and save. Error 0271 will not return.

When to Call a Professional

Replacing the CMOS battery is a DIY repair on most ThinkPads — the battery is accessible after removing the bottom panel. A technician is only needed if the battery socket itself is damaged.