How to Reset the Real-Time Clock (RTC) to Recover Your Dell Desktop System

The Real-Time Clock (RTC) is a small chip on your computer's motherboard that keeps track of the current date and time, even when your computer is turned off. It runs on a small battery and helps your computer remember important timing settings.

Sometimes, the RTC can store incorrect information that prevents your computer from starting properly. Resetting the RTC clears this information and restores your computer to working settings.

Use this reset procedure if your Dell desktop computer:

• Won't turn on when you press the power button.
• Turns on but shows a black screen.
• Powers on but won't start Windows.
• Can not find your hard drive or operating system.

Troubleshooting your laptop? Check out our guide to reset RTC on a laptop.

Step 1: Reset the real-time clock

1. Find the power button on your computer.
2. Press and hold the power button.
3. Keep holding for 30 full seconds.
   • Keep holding even if lights flash or you hear beeps.
   • Do not release the button early.
4. After 30 seconds, release the power button.
5. Do not touch anything for the next 2-5 minutes.

What happens next:

Your computer automatically begins the reset process. You may see:

• Power lights flashing on and off.
• Keyboard backlight turning on and off.
• Fans starting and stopping.
• The computer restarting itself 2-3 times.
• Brief beeping sounds.

The reset is complete when:

You see the Dell logo on your screen and your computer starts normally.

Step 2: Complete the setup

After the reset completes and you see the Dell logo:

1. Your computer may display a message about date and time settings.
2. Press any key to continue.
3. Windows loads normally.
4. Check your date and time.
   • Select Start > Settings > Time & Language.
   • Make sure the date and time are correct.
   • Windows usually sets these automatically when connected to the internet.

If you need to enter BIOS settings:

1. Restart your computer.
2. Press F2 repeatedly as soon as you see the Dell logo.
3. Check that your boot order shows your hard drive first.
4. Save changes and exit the BIOS.

What this reset changes

Settings that reset to defaults

• Current date and time.
• Boot order (which drives the computer checks first).
• Fast startup settings.
• Some hardware configurations.

Settings that stay the same

• All your files, photos, and documents.
• Your Windows operating system.
• Installed programs and applications.
• Your passwords and user accounts.
• Everything on your hard drive.

Settings that might change

These settings reset only if you previously changed them from defaults:

• Secure Boot (may turn back on).
• Trusted Platform Module or TPM settings.
• Virtualization settings.
• Custom memory timings.
• Fan control settings.

If you use BitLocker encryption: You may need to enter your BitLocker recovery key after the reset. Have this key ready before you begin.

Check if your computer supports RTC reset

Your Dell desktop is expected to support RTC Reset, if it is one of these models from April 2020 or newer:

Inspiron Desktops

Inspiron 3471, 3660, 3671, 3880, 3881, 3888, 3891, 5090, 5300, 5400, 5490, 5491, 5676, 5680, 7300, 7400, 7500, 7501, 7700, 7706, 7707

OptiPlex Desktops

OptiPlex 3070, 3080, 3090, 3280, 5070, 5080, 5090, 5260, 5270, 5480, 5490, 7010 Plus, 7070, 7071, 7080, 7090, 7480, 7490, 7760, 7770, 7780

Note: All OptiPlex sizes (tower, small form factor, and micro) use the same reset method.

Precision Desktops

Precision 3240, 3430, 3440, 3630, 3640, 3650, 5820, 7820, 7920

Vostro Desktops

Vostro 3471, 3670, 3671, 3681, 3690, 3888, 3891, 5090

XPS Desktops

XPS 8940, 8950

Dell Pro Max Micro

All

Dell Pro Max Slim

All

Dell Pro Max Tower

All

Dell Pro Micro

All

Dell Pro Slim

All

Dell Pro Tower

All

Dell Slim Desktops

All

Dell Tower Desktops

All

Dell Pro Max Micro XE Desktops

All

Dell All-in-One Desktops

All

Recommended Verification

1. Visiting Dell Support and entering your Service Tag.
2. Reviewing your system's Setup and Specifications Guide.
3. Look for "Clear CMOS" or "RTC Reset" instructions.

Troubleshooting

The computer still will not turn on

Try these steps:

1. Unplug the power cord from the computer.
2. Wait 30 seconds.
3. Plug the power cord back in.
4. Repeat the reset process from Step 3.
5. Make sure you are plugging directly into a wall outlet, not a power strip.

Check your power connection:

• Try a different power outlet.
• Make sure the power cord is fully inserted at both ends.
• Look for a power switch on the back of the computer and make sure it is on.
• If you have a power strip, bypass it and plug directly into the wall.

The reset starts but never finishes

If you see lights flashing but no Dell logo after 10 minutes:

1. Press and hold the power button for 10 seconds to force shutdown.
2. Wait 30 seconds.
3. Try the reset process one more time.
4. If it still does not finish, try some steps to fix startup problems.

The computer starts but shows an error message

"Time-of-day not set" or similar date/time error:

1. Enter BIOS Setup by pressing F2 at the Dell logo.
2. Set the correct date and time.
3. Select Exit and save changes.
4. This is normal after a reset.

"Boot device not found" error:

1. Enter BIOS Setup by pressing F2 at the Dell logo.
2. Go to the Boot Sequence section.
3. Move your hard drive to the top of the list.
4. Save changes and exit the BIOS.

BitLocker recovery key request:

1. Enter your 48-digit BitLocker recovery key.
2. Your computer starts normally after entering the key.
3. You only need to do this once.

You can find your BitLocker recovery key:

• In your Microsoft account at account.microsoft.com/devices.
• On a USB drive if you saved it there.
• In a printout if you printed it when enabling BitLocker.

I have an older computer with a jumper

For computers made before April 2020:

You will need to clear the CMOS using the motherboard jumper.

1. Shut down and unplug your computer.
2. Open the computer case.
3. Find the CMOS jumper on the motherboard.
   • Usually labeled "CLR_CMOS," "CLEAR CMOS," or "RTC_RST".
   • Located near the coin cell battery.
4. Move the jumper to the clear position for 10 seconds.
5. Move the jumper back to its original position.
6. Close the case and plug in your computer.

Find detailed instructions:

1. Go to Dell.com/support.
2. Enter your service tag.
3. Select Documentation.
4. Download your service manual.
5. Search for "clear CMOS" or "RTC reset".

Frequently asked questions

Will this delete my files?

No. This reset only changes hardware timing settings. Your documents, photos, programs, and Windows installation are not affected.

Is this safe to do?

Yes. This is a standard troubleshooting step recommended by Dell. It will not damage your computer or void your warranty.

How many times can I do this reset?

As many times as needed. The reset will not harm your computer.

My keyboard lights up during the reset. Is this normal?

Yes. The keyboard backlight may turn on and off several times. This is part of the normal reset process.

The screen stays black, but I hear the fans. What should I do?

Keep waiting. The computer restarts itself several times during the reset. If nothing happens after 10 minutes, try the troubleshooting steps above.

Do I need to press F2 or F12 during the reset?

No. Just hold the power button for 30 seconds and release. The reset happens automatically.

Can I do this if my computer is under warranty?

Yes. This procedure does not void your warranty and is recommended by Dell as a first troubleshooting step.

What is the difference between this and removing the CMOS battery?

The power button reset does the same thing as removing the battery or moving the jumper, but it is easier and does not require opening your computer.

My computer is connected to a UPS or surge protector. Is that okay?

For best results, plug directly into a wall outlet during the reset. Some UPS devices may interfere with the reset process.

After the reset, my BIOS settings changed. Is this normal?

Yes. The reset returns BIOS settings to factory defaults. You may need to adjust settings like boot order, date and time, or Secure Boot if you changed them before.