在Windows中，CMOS代表互补金属氧化物半导体(Complementary Metal-Oxide Semiconductor)。它是位于计算机主板上的电池供电内存。该术语还描述了一种内存技术，可帮助您 PC 上的Basic Input/Output System( BIOS ) 程序存储重要的系统数据，如日期和时间设置、启动顺序、磁盘驱动器信息和其他系统配置。
如果此内存有问题，您的 PC 将在启动Windows(Windows)之前显示“CMOS Checksum Bad”错误。在本指南中，我们将向您展示导致错误的原因以及如何修复它。
什么导致Windows 中的CMOS(Windows)校验和错误(CMOS Checksum Error)？
“校验和(Checksum)”描述了一个值（数字或字母），用于监控或验证存储设备中文件的完整性。如果CMOS(CMOS)内存中的值损坏，您将在 PC 上收到“ CMOS Checksum Bad”错误。(CMOS)这可能是由于安装了不正确或损坏的BIOS更新。CMOS本身由专用电池供电，因此如果 CMOS 电池电量不足、损坏或陈旧，您也可能会收到CMOS校验(CMOS)和错误(CMOS)。
电源浪涌或不正确地将 PC 从电源插座断开也可能导致CMOS校验和错误。尽管有许多致病因素，但“ CMOS Checksum Bad”很容易修复。
有趣的事实：(Fun Fact:) CMOS也称为实时时钟(Clock)( RTC )、互补对称金属氧化物半导体(Metal-Oxide-Semiconductor)( COS-MOS ) 或非易失性RAM ( NVRAM )。
如何修复 CMOS 校验和错误
如果您的Windows PC 在启动时显示“CMOS Checksum Bad”错误，下面列出的故障排除解决方案应该可以解决问题。
执行自动修复
您还可以使用启动修复(Start-Up Repair)工具来修复阻止Windows正确启动的问题。关闭(Shut)计算机并按照以下步骤操作。
- 如果您的 PC 已开机，请前往设置(Settings)>更新和安全(Update & Security)>高级启动(Advanced startup)>立即重启(Restart Now)。
如果Windows无法启动，请关闭计算机并重新打开电源。屏幕亮起时，反复按F8或F11键，直到屏幕出现高级启动菜单。
加载高级启动菜单的另一种方法是连续三次重新启动 PC。也就是说，打开您的 PC 并立即按住电源按钮，直到您的 PC 关闭。重复三次，您的 PC 应该在第三次尝试时加载高级启动菜单。
- 选择疑难解答(Troubleshoot)。
- 选择高级选项(Advanced options)。
- 选择启动修复(Start-up Repair)。
- 输入您的帐户密码点击继续(Continue)。如果您的帐户不受密码保护，请将该对话框留空，然后单击继续。(Continue)
该工具将诊断您的 PC 并尝试修复所有阻止其正确启动的系统错误。操作完成后重新启动计算机并检查是否修复了CMOS校验和。
将 BIOS 重置为出厂默认设置
执行BIOS重置将清除CMOS中保存的所有信息。从积极的方面来说，该操作还将删除损坏的数据和不正确的BIOS值。如何访问BIOS并将其重置为出厂默认设置取决于您的主板和 PC 的品牌。
有关更多信息，请参阅我们在 Windows 中重置 BIOS 的教程。(our tutorial on resetting BIOS in Windows)确保在重置BIOS后重新启动计算机。这将重建校验和值并修复CMOS错误。
在错误页面上按F1或F2进入BIOS设置页面并选择Load Defaults、Load Set Defaults或分配给将(Load Set Defaults)BIOS恢复为默认值的任何选项。
某些计算机可能需要您按不同的键（通常是Del或F8）才能进入 Windows BIOS 设置页面(enter the Windows BIOS setup page)。检查错误页面上的说明以确定。
如果您退出了错误页面，您可以从Windows 高级启动(Windows Advanced Startup)菜单重置BIOS 。关闭您的 PC 并等待大约 20-30 秒以使其完全关闭。
- (Press)在 PC 启动时，恰好在Windows徽标出现在屏幕上之前，按下电源按钮并按住F8或F11键。(F11)
- 选择疑难解答(Troubleshoot)。
- 选择高级选项(Advanced options)。
- 选择UEFI 固件设置(UEFI Firmware Settings)。
- 单击重新启动(Restart)以将您的 PC 引导至BIOS设置实用程序。
BIOS设置界面将根据您的 PC 品牌而有所不同。尽管如此，您应该在BIOS(BIOS)实用程序的“退出”部分找到重置BIOS的选项。
- 转到 Exit，使用向下箭头键将选择器移动到Load Default Settings，然后按Enter。
如果您没有找到将BIOS设置重置为默认值的选项，请联系您的 PC 制造商或查看您设备的说明手册。
- 选择Yes并按Enter。
- 将光标移动到Exit Saving Changes并按Enter。
这会将您的 PC 的BIOS恢复为默认设置并启动Windows。要确认这是否解决了问题，请关闭您的 PC 并重新打开它。如果您的 PC 启动时仍然出现“CMOS Checksum Bad”错误，请尝试下一个故障排除步骤。
更新 BIOS
如果您的PC 的 BIOS 版本(PC’s BIOS version)与制造商网站上的最新版本不对应，您应该执行BIOS更新（检查“驱动程序下载”或“ BIOS ”部分）。下载包含与您的 PC 型号匹配的更新的BIOS实用程序，以管理权限运行它，然后让该工具自动更新您设备的BIOS。
在继续之前，请了解BIOS是 PC 主板的一个精密组件。安装不正确的更新或错误地更新BIOS可能会对主板造成永久性损坏。请按照 PC 制造商的说明进行操作，以免损坏您的设备。
也就是说，我们强烈建议您仅从 PC 制造商的网站下载BIOS文件。(BIOS)此外，请特别确保BIOS更新属于您的 PC 型号。在您的 PC 上安装其他设备的BIOS文件会使主板变砖。
最后，不要在BIOS更新期间关闭或重新启动 PC。操作期间的任何中断（例如，电涌或断电）都可能损坏BIOS或主板。
更换 CMOS 电池
如前所述，如果为CMOS供电的电池电量不足，您的计算机可能无法验证BIOS文件的完整性。CMOS电池故障的迹象包括不正确的数据和时间、(Signs)无响应的外围设备(unresponsive peripherals)、连接到互联网的问题等。
如果在尝试这些故障排除修复后仍然出现CMOS校验和错误，则CMOS电池可能坏了。或者，它可能偏离了它的位置。
如果您是熟练的计算机技术人员，您应该只尝试重新调整或更换CMOS电池。(CMOS)否则，请访问附近的维修中心或联系您的 PC 制造商。
检查硬件损坏
PC 主板的部分或完全损坏也可能触发“CMOS Checksum Bad”错误。将您的 PC 带到维修中心，检查您的主板是否有物理损坏。
How to Fix a CMOS Checksum Error
In Windowѕ, CMOS stands for Complementary Metal-Оxide Semiconductor. It is a batterу-рowered memory located on your computer’s motherboard. The term also describes a memory technology that helps the Basic Input/Output System (BIOS) program on your PC store vital system data like date & time settings, boot sequence, disk drive іnformation, and other system confіgurations.
If there’s a problem with this memory, your PC will display a “CMOS Checksum Bad” error before it boots Windows. In this guide, we’ll show you what causes the error and how to get it fixed.
What Causes CMOS Checksum Error in Windows?
“Checksum” describes a value (number or letter) used to monitor or verify the integrity of files in a storage device. You’ll get the “CMOS Checksum Bad” error on your PC if values in the CMOS memory are corrupt. This could be due to installing an incorrect or corrupt BIOS update. The CMOS itself is powered by a dedicated battery, so you might also get the CMOS checksum error if the CMOS battery is weak, bad, or old.
Power surges or improperly disconnecting your PC from a power outlet can also cause the CMOS checksum error. Despite having numerous causative factors, the “CMOS Checksum Bad” is easy to fix.
Fun Fact: CMOS is also referred to as Real-Time Clock (RTC), Complementary-Symmetry Metal-Oxide-Semiconductor (COS-MOS), or Non-Volatile RAM (NVRAM).
How to Fix CMOS Checksum Bad Error
If your Windows PC displays a “CMOS Checksum Bad” error when booting up, the troubleshooting solutions listed below should resolve the problem.
Perform an Automatic Repair
You can also use the Start-Up Repair tool to fix issues preventing Windows from booting correctly. Shut down your computer and follow the steps below.
- If your PC is powered on, head to Settings > Update & Security > Advanced startup > Restart Now.
If Windows won’t boot, shut down your computer and power it back on. When the screen lights up, press the F8 or F11 key repeatedly until the advanced startup menu comes on the screen.
Another way to load the advanced startup menu is to restart your PC in three successions. That is, power on your PC and hold the power button immediately until your PC goes off. Repeat that three times and your PC should load the advanced startup menu on the third try.
- Select Troubleshoot.
- Select Advanced options.
- Select Start-up Repair.
- Enter your account’s password click Continue. Leave the dialog box empty and click Continue if your account isn’t password-protected.
The tool will diagnose your PC and attempt to fix all system errors preventing it from booting correctly. Restart your computer when the operation reaches completion and check if that fixes the CMOS checksum.
Reset BIOS to Factory Default
Performing a BIOS reset will erase all information saved in the CMOS. On the positive side, the operation will also remove corrupt data and incorrect BIOS values. How you access your BIOS and reset it to factory default would depend on your motherboard and your PC’s brand.
Refer to our tutorial on resetting BIOS in Windows for more information. Ensure you reboot your computer after resetting BIOS. That’ll rebuild the checksum values and fix the CMOS error.
Press F1 or F2 on the error page to enter the BIOS setup page and select Load Defaults, Load Set Defaults, or whatever option is assigned to restoring BIOS to default.
Some computers may require you to press a different key (usually Del or F8) to enter the Windows BIOS setup page. Check the instructions on the error page to be sure.
If you exited the error page, you can reset the BIOS from the Windows Advanced Startup menu. Power off your PC and wait for about 20-30 seconds for it to shut down completely.
- Press the power button and hold the F8 or F11 key as your PC boots up, precisely before the Windows logo appears on the screen.
- Select Troubleshoot.
- Select Advanced options.
- Select UEFI Firmware Settings.
- Click Restart to boot your PC to the BIOS setup utility.
The BIOS setup interface will vary based on your PC’s brand. Nonetheless, you should find the option to reset BIOS in the “Exit” section of the BIOS utility.
- Go to the Exit, use the arrow-down key to move the selector to Load Default Settings, and press Enter.
If you don’t find the option to reset the BIOS settings to default, contact your PC’s manufacturer or check your device’s instruction manual.
- Select Yes and press Enter.
- Move the cursor to the Exit Saving Changes and press Enter.
That will restore your PC’s BIOS to default settings and boot Windows. To confirm if that fixed the problem, shut down your PC and turn it back on. Try the next troubleshooting step if you still get the “CMOS Checksum Bad” error when your PC comes on.
Update BIOS
You should perform a BIOS update if your PC’s BIOS version doesn’t correspond with the latest version on the manufacturer’s website (check the “Driver Download” or “BIOS” section). Download the BIOS utility containing the update that matches your PC model, run it with administrative privileges, and let the tool automatically update your device’s BIOS.
Before you proceed, understand that the BIOS is a delicate component of your PC’s motherboard. Installing the incorrect update, or updating BIOS wrongly, can do permanent damage to the motherboard. Follow the PC manufacturer’s instructions to the letter so you don’t ruin your device.
That said, we strongly advise that you download BIOS files only from your PC manufacturer’s website. Also, be extra sure that the BIOS update belongs to your PC model. Installing another device’s BIOS file on your PC will brick the motherboard.
Finally, do not power off or restart your PC during the BIOS update. Any interruption (e.g., power surge or outage) during the operation can damage the BIOS or motherboard.
Replace the CMOS Battery
As mentioned earlier, your computer may be unable to verify the integrity of BIOS files if the battery powering the CMOS is weak. Signs of a failing CMOS battery include incorrect data & time, unresponsive peripherals, problems connecting to the internet, etc.
If you still get the CMOS checksum error after trying these troubleshooting fixes, the CMOS battery is probably bad. Or perhaps, it’s displaced from its position.
You should only attempt to readjust or replace the CMOS battery if you’re a skilled computer technician. Otherwise, visit a nearby repair center or contact your PC manufacturer.
Check for Hardware Damage
Partial or complete damage to your PC’s motherboard can also trigger the “CMOS Checksum Bad” error. Take your PC to a repair center to get your motherboard examined for physical damage.
