How to fix webcam error code 0xA00F4243(0xC00D3704) on Windows?

Error 0xA00F4243 <CameraReservedByAnotherApp> (0xC00D3704) means Windows could not start the webcam because another app or process already holds it. Microsoft lists it under that exact cause. Close every app that may use the camera, end it in Task Manager and restart Windows; if no app is open, look at the USB port and the camera driver.

Facts checked on 15 October 2026. Steps written for Windows 11 (25H2 and 26H2) and Windows 10 22H2.

What webcam error 0xA00F4243 (0xC00D3704) means

The Windows Camera app shows the heading Close other apps and the line It looks like another app is using the camera already. Below it, after If you need it, here's the error code, comes 0xA00F4243<CameraReservedByAnotherApp> (0xC00D3704). On older Windows 10 builds the code is written without the name, as 0xA00F4243(0xC00D3704).

Both parts say the same thing. 0xA00F4243 is the Camera app's code for a camera reserved by another app. 0xC00D3704 is a Media Foundation code, from the part of Windows that handles video. Its text is: the hardware failed to start streaming due to lack of hardware resources. The missing resource is the camera itself, which another program has opened first.

Why the camera is reserved by another app

Most often an app you closed is still running: Teams, Zoom, Skype or Discord minimised to the tray, a browser tab with a video call, or OBS or a virtual camera tool. Often a background program or service grabs the camera when Windows starts. Less often a USB hub or dock makes the webcam look busy, or the driver hangs after sleep. Rarely security software or a damaged Camera app is behind it.

How to fix camera error 0xA00F4243 <CameraReservedByAnotherApp> (0xC00D3704)

Fixes 1 to 4 find and close whatever holds the camera, which ends the error for most readers. Fix 5 covers blocked access, which Microsoft lists under the same code. Fixes 6 to 8 come last, for a driver, a Camera app or security software at fault.

Fix 1. Close every app that may use the camera and restart Windows

5 minutesNo riskEveryone, first. Especially when a call app, a browser call or a streaming tool was open today.

The message means exactly this: another app has the camera. Microsoft's steps for 0xA00F4243 are to close the apps that might use it and end them in Task Manager. A restart closes anything you could not find.

1. Quit Teams, Zoom, Skype, Discord, OBS and any camera or virtual camera tool. Check the tray near the clock: right-click each icon and select Quit or Exit.
2. Close browser tabs that had a video call or a webcam test.
3. Press Ctrl + Shift + Esc to open Task Manager. Under Apps and Background processes, select any app that may use the camera and select End task.
4. Restart Windows with Start > Power > Restart. Waking the PC from sleep is not the same thing.
5. Open Start > Camera before any other app and check the preview.

Fix 2. Plug a USB webcam straight into the PC

2 minutesNo riskAn external USB webcam that sits on a USB hub, a dock or a monitor's USB port.

Microsoft's first driver step for an external camera is to try another USB port. Users on Microsoft's own forum report that 0xA00F4243 (0xC00D3704) stopped when they moved the webcam from a USB hub to a port on the computer.

1. Close the Camera app.
2. Unplug the webcam from the hub, dock or monitor.
3. Plug it into a USB port on the PC itself, on the back of a desktop.
4. Wait a few seconds until Windows finds it, then open Camera.

Fix 3. Disable and enable the camera to release it

5 minutesLow riskNo app is open, but the camera still reads as busy, often after the PC woke from sleep.

Disabling the camera closes every connection to it, including one a crashed app left behind. Enabling it starts the driver fresh, without a full reinstall. Administrator access is needed.

1. On Windows 11, open Settings > Bluetooth & devices > Cameras.
2. Under Connected cameras, select your camera and select Disable, then Yes.
3. Under Disabled cameras, select it again and select Enable.
4. On Windows 10, or if Settings has no button: right-click Start, select Device Manager, and expand Cameras or Imaging devices.
5. Right-click the camera, select Disable device and confirm. Right-click it again and select Enable device.
6. Open the Camera app.

Fix 4. Find the background program with a clean boot

20 minutesLow riskThe error is there right after a restart, and you closed every app you know of.

A clean boot starts Windows with Microsoft services only. If the camera then works, a program from another company opened it at startup. It was also the first answer to this exact error on Microsoft's forum.

Start Windows with Microsoft services only and test the camera: How to perform a clean boot in Windows

1. Run the clean boot as the procedure says and restart.
2. Open Start > Camera before anything else and check the preview.
3. Note whether the error is gone, then read the list below.

• The camera works now: turn services and startup apps back on in small groups and test after each restart. The group that brings the error back holds the program.
• Suspects: camera and webcam utilities, virtual camera tools, call apps set to start with Windows, screen recorders.
• When you find it: turn off its start with Windows, or update or remove it. Then undo the clean boot as the procedure says.

Fix 5. Allow apps and desktop apps to use the camera

3 minutesNo riskTeams, Zoom or a browser shows a camera in use warning while the Camera app works, or nothing above helped.

Microsoft lists 0xA00F4243 together with access errors and gives privacy settings as the second step. After a Windows 11 update some apps lose camera access by default, and desktop apps depend on one extra switch.

1. Open Start > Settings > Privacy & security > Camera.
2. Turn on Camera access.
3. Turn on Let apps access your camera, and switch on Camera and any Store app you use in the list.
4. Turn on Let desktop apps access your camera. Browsers and Teams need this switch; you cannot allow single desktop apps.
5. Open the app again and start the camera.

Fix 6. Roll back or reinstall the camera driver

15 minutesLow riskNo program holds the camera in a clean boot, the camera has a warning sign, or the error began after a driver update.

A hung or damaged driver can report the camera as busy when nothing uses it. Microsoft's order is a rollback after an update, then uninstall and scan for hardware changes, then the maker's driver.

1. In Device Manager, right-click the camera and select Properties, then open the Driver tab.
2. If Roll Back Driver is available, select it, choose a reason and select Yes. Restart and test.
3. If not, select Uninstall Device, tick Attempt to remove the driver for this device and select OK.
4. Open the Action menu and select Scan for hardware changes, then restart.
5. If the error stays, install the newest camera driver for your exact model from the laptop or webcam maker's support page.

For a USB webcam, Microsoft also suggests the driver built into Windows: Update driver > Browse my computer for drivers > Let me pick from a list of available drivers on my computer > USB Video Device. It may not support every feature, such as Windows Hello face sign-in. Full driver steps: Update, roll back or reinstall a driver

Fix 7. Repair or reset the Windows Camera app

5 minutesLow riskThe camera works in Teams, Zoom or a browser, and only the Camera app shows 0xA00F4243.

When other apps get video from the same camera, nothing holds it at the system level. The fault then sits in the Camera app's own files or settings, which Repair and Reset replace.

1. Close the Camera app.
2. Open Settings > Apps > Installed apps, find Camera, select the three dots and select Advanced options.
3. Select Repair and test the app.
4. If it still fails, select Reset. Settings go back to default; photos and videos in Pictures > Camera Roll stay.

On Windows 10 the path is Settings > Apps > Apps & features > Camera > Advanced options. Full steps: How to repair or reset an app in Windows

Fix 8. Check the webcam protection in your security software

5 minutesLow riskYour security suite has a webcam or privacy shield, and the error remains.

Microsoft's steps for 0xA00F4243 end with making sure antivirus or other security software is not blocking the camera. A webcam shield sits between the camera and every app.

1. Open your security program and look for a webcam protection or privacy setting.
2. Allow the Camera app and the call app you use, rather than turning protection off.
3. To test, pause protection for a single camera test, then turn it on again: Turn off Microsoft Defender protection for a moment

If 0xA00F4243 is still there

Write down the full message and any second code each time; it can change, for example to the stream error 0xA00F4271, which has its own guide to webcam error 0xA00F4271. Then run three short tests to tell software from hardware.

1. Run the camera troubleshooter: Settings > System > Troubleshoot > Other troubleshooters > Camera > Run. On Windows 11 it may open in the Get Help app.
2. Start Windows in safe mode and open the Camera app once, to rule out every other program: Start Windows or a Mac in Safe Mode
3. For a USB webcam, try it on another PC.

• When it is hardware: the camera vanishes from Device Manager after Scan for hardware changes, or a USB webcam fails on a second PC as well.
• What to send to support: the full message with both codes, the camera name and driver version from Device Manager, the PC model from msinfo32 and the Windows version from Settings > System > About.
• Who to ask: for a built-in camera, the laptop maker; for a USB webcam, its maker; on a work PC, your IT admin.

How to keep the camera from being reserved again

Windows 10 left support on 14 October 2025, so new camera fixes from Microsoft reach it less often. The steps on this page still work on Windows 10 22H2.

Frequently asked questions

What does 0xA00F4243 <CameraReservedByAnotherApp> (0xC00D3704) mean?

It means the camera is already in use by another app or process, so the app you opened cannot start the video. Microsoft's camera help gives exactly this cause for 0xA00F4243. The second code, 0xC00D3704, is a Windows video error that says the hardware failed to start streaming due to lack of hardware resources; the resource is the camera. Close every app that may use it and restart Windows (Fix 1).

How do I find which app is using my camera?

Start with the usual suspects: Teams, Zoom, Skype, Discord, OBS, virtual camera tools and browser tabs with a call. Check the tray near the clock, because many call apps keep running there after you close the window. In Task Manager, look under Apps and Background processes and end them (Fix 1). If you cannot find it, a clean boot shows whether a program from another company opens the camera at startup, and turning items back on in groups points to the one (Fix 4).

Why does it say camera reserved by another app when no app is open?

The program can be hidden: a background process, a service that starts with Windows, or a call app minimised to the tray. A driver that hung after sleep can also report the camera as busy. Restart Windows rather than waking it from sleep (Fix 1), then disable and enable the camera (Fix 3). For a USB webcam, a hub or dock can cause the same error, and users report that a port on the PC itself fixed it (Fix 2).

How do I fix 0xA00F4243 on Windows 11?

Close camera apps and restart (Fix 1). Plug a USB webcam directly into the PC (Fix 2). Then go to Settings > Bluetooth & devices > Cameras, disable the camera and enable it again (Fix 3). Check that Camera access, Let apps access your camera and Let desktop apps access your camera are on in Privacy & security > Camera (Fix 5). If the error stays, roll back or reinstall the camera driver (Fix 6). Windows 10 uses the same fixes with Device Manager and Settings > Privacy > Camera.

Can two apps use the webcam at the same time?

Usually not. Most webcams let one app at a time open them, and the second app gets this error. That is why a Teams call and the Camera app, or Zoom and a browser test, cannot share the camera. Close one before you open the other. Some virtual camera tools pass the picture on to several apps, but they also hold the real camera themselves, so close them too when you see 0xA00F4243.

Why does my webcam fail even after I reset the Camera app?

Because a reset only touches the Camera app, and this error is about another program holding the camera. If the camera also fails in Teams, Zoom or a browser, the cause is outside the app: a background program (Fix 4), the USB port (Fix 2) or the driver (Fix 3 and Fix 6). A reset helps only when the camera works in other apps and fails in Camera alone (Fix 7).

Can malware cause the camera reserved by another app error?

It is possible but uncommon. In most cases the program holding the camera is a normal call, streaming or camera tool. If a clean boot shows a program you do not recognise opening the camera at startup, look it up, remove it if you did not install it, and run a full scan with Microsoft Defender or your own security software. Do not assume malware before you have checked the usual apps in Fix 1 and Fix 4.

Is my webcam broken if I see 0xA00F4243?

Usually not. The code means the camera is busy, not damaged, and closing the program that holds it ends the error. Hardware is likely only when the camera disappears from Device Manager even after Scan for hardware changes, or when a USB webcam also fails on another PC. A built-in camera then needs the laptop maker's service; a USB webcam can be replaced.

I searched in another language. Does this page fit my error?

Yes, if your screen shows 0xA00F4243 or 0xC00D3704. The codes are the same in every language of Windows; only the message around them is translated, such as Close other apps. The menu names here are in English but sit in the same places in other languages. If your code is different, for example 0xA00F4244 for no camera found, search for that exact code, because its first fix is different.