Will Dead CMOS Battery Prevent Boot?

The most frequent thing that people have pondered is, can dead CMOS battery prevent boot? Dead CMOS battery might cause malfunctions to some set up on your computer. This is because the battery helps to maintain data, including the time and date settings, which are stored in CMOS memory. Without power from a working CMOS battery, you won’t have this information to set the system clock (time and date) when the machine boots up. If you’re unsure if your CMOS battery needs replacing, there are some signs that can help determine whether or not it’s on its last legs.

What happens if your CMOS battery dies? 

The CMOS (Complementary Metal-Oxide Semiconductor) battery powers a small memory chip on the motherboard. The data in this chip include system clock settings (time/date), disk information, and various system configurations.

The battery is usually located next to the memory chips on the motherboard. It helps the computer remember time/date even when it’s turned off or unplugged from the power source for a long time period. Usually, CMOS batteries are either lithium coin cell type or silver oxide type button cells with wires attached to the motherboard.

When the CMOS battery dies, the computer will not be able to save BIOS settings like date and time. A computer might fail to boot or freeze at the startup screen when you turn it on next time after that because your system clock is incorrect. The same thing happens when you change the BIOS settings but forget to backup your data before turning off the computer.

If this is not a critical issue for you, then simply replace the battery with a new one to resolve the problem. If it’s an old computer that doesn’t have a CMOS battery or you simply don’t have a spare battery, then you can also use BIOS jumper settings to clear CMOS.

Remove the computer cover and locate the dead or missing batteries on the motherboard. Follow instructions of your motherboard manual on how to replace it if necessary.

Can CMOS battery cause computer not start?

Your system might start having problems with startup errors and other issues as well, due in part to lack of power onboard during boot-up cycles (CMOS).

When the CMOS battery starts to lose power and strength, your computer’s BIOS loses data. This can cause an issue with how the computer of your operating system works on a daily basis. Some signs of this problem could include:

The machine turning off or not starting at all – Alongside errors about needing maintenance from time to appearing while booting up, Verbose messages tell you when there’s been corruption in memory.

Will dead CMOS battery prevent boot?

In general, the dead CMOS battery will not prevent your computer from booting. You just lose date and time.

You can reset the CMOS battery by removing it for about two minutes and put back. But make sure to shut down your computer before doing this. If not, you will lose the date again when restarting.

Will a dead CMOS battery prevent power on?

A dead CMOS battery means your BIOS does not have the date and time, making it unable to start accurately when power is turned on. If you can’t find a CMOS battery that still holds a charge from somewhere out in the wild, then yes, it will prevent you from turning on the computer. You’ll need to replace the CMOS battery for this fix.

Can you boot without CMOS battery?

If you can boot without a CMOS battery, it means that your BIOS does not need the date and time in order to start up correctly. This is usually because the motherboard has an RTC (real-time clock) integrated into it.

The CMOS battery is one of the most important components in a PC motherboard because it keeps BIOS configuration settings alive. Receiving power even when the computer is turned off, CMOS batteries make it possible to change BIOS settings and record data.


Knowing how CMOS battery works can help you prevent future problems that may arise if your BIOS settings are lost. As soon as you notice that your laptop‘s date and time are not correct, you should find a new CMOS battery to put on the motherboard.

You might have a dead CMOS battery if your laptop won’t boot. If you’re experiencing this issue, it’s important to take care of the problem as soon as possible because your computer could be permanently damaged without regular maintenance. Fortunately, there are some relatively easy ways that you can prevent or at least minimize these types of problems in the future by taking simple steps like using power management features and making sure your CMOS is set correctly.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.