how to fix error code:0xA00F4240<Unknown> (0.80004003)

Run the Windows Camera troubleshooter first, because Microsoft specifically associates error 0x80004003 with a camera device-detection problem and recommends automated diagnostics followed by driver repair.^1^

1. Run the Camera troubleshooter

Windows 11

1. Open Start → Settings → System → Troubleshoot → Other troubleshooters.
2. Find Camera and select Run.
3. Apply any recommended repair, restart Windows, and test Start → Camera.

Windows 10

1. Open Start → Settings → Update & Security → Troubleshoot.
2. Under Find and fix other problems, select Camera → Run the troubleshooter.
3. Apply the repair, restart, and test the Camera app.^1^

2. Check camera access and physical controls

On Windows 11, open Settings → Privacy & security → Camera, then turn on:

• Camera access
• Let apps access your camera
• Let desktop apps access your camera if the problem affects a browser, Teams, Zoom, or another desktop program

If Camera access is greyed out, an administrator must enable it.

Also check for a privacy shutter, side switch, camera key, or Fn + camera-key combination. A disabled hardware switch can prevent Windows from detecting the camera at all.^1^

3. Repair the camera driver

If the problem began immediately after a Windows or driver update:

1. Right-click Start → Device Manager.
2. Expand Cameras, Imaging devices, or Sound, video and game controllers.
3. Right-click the camera and select Properties → Driver → Roll Back Driver.
4. Restart Windows and test the Camera app.

If rollback is unavailable or does not fix it:

1. In Device Manager, right-click the camera and select Properties.
2. Open Driver → Uninstall Device.
3. Select Attempt to remove the driver for this device or Delete the driver software, if offered.
4. Select Uninstall.
5. Open Action → Scan for hardware changes.
6. Restart the computer and test the camera.

Removing the driver temporarily disables the camera; Windows should detect and reinstall it during the scan or restart.^1^

4. If the camera is missing from Device Manager

1. In Device Manager, select Action → Scan for hardware changes.
2. If it remains absent, install the camera/chipset driver supplied for the exact computer model from the PC manufacturer.
3. For an external webcam, reconnect it through another USB port and avoid an unpowered USB hub while testing.

If an external USB webcam is listed but still fails, and it supports USB Video Class (UVC), an administrator can try the Windows inbox driver:

1. Right-click the webcam → Update driver.
2. Select Browse my computer for drivers.
3. Select Let me pick from a list of available drivers on my computer.
4. Choose USB Video Device → Next.

The generic UVC driver can omit manufacturer-specific features, potentially including Windows Hello facial recognition.^1^

5. Windows 11 24H2 or later

Try Basic camera mode if manufacturer plug-ins or hardware acceleration are interfering with camera operation. This option applies only to Windows 11 version 24H2 and later.^1^

If the camera works in another application but only the Windows Camera app reports this error—particularly on an Insider Preview build—the issue may be build-specific. One matching report for Insider build 26220.8680 showed the same 0xA00F4240 (0x80004003) error while the webcam continued working in OBS and browsers.^2^ In that case, install the next available Insider update and report the problem through Feedback Hub rather than repeatedly replacing the hardware driver.

References

1. Windows 10 (#tab/windows-10)
2. Windows Camera App Fails with Error 0xA00F4240 on Insider Build 26220.8680 While Webcam Works in Other Applications - Microsoft Q&A