Hello Jonathan,
Thank you for posting question on Microsoft Windows Forum!
Based on the issue description. Well! The plausible explanation for this symptom is that the modern Windows Camera app is built on the Universal Windows Platform (UWP) framework, which treats the camera and microphone as a bundled "media capture" package. When the app initializes, it checks for access to both streams via the Windows Media Foundation API. If the microphone permission is toggled "Off" in the Privacy settings, the API returns a "Permission Denied" error for the entire capture session, causing the app to crash or refuse to open, regardless of whether you are in photo or video mode.
The suggested workaround is to disable the Microphone in sound settings. This will allow the app to function without feeding it any audio. You can go to Settings > System > Sound. Scroll down to the Input section. Click on your active microphone (e.g., "Microphone Array" or "Realtek Audio"). Under General, find Audio, and click "Don't allow". Now, go to Settings > Privacy & Security > Microphone and ensure "Let apps access your microphone" and the "Camera" app toggle are both On. Because the device itself is disabled at the system level, the Camera app will "see" that it has permission to listen, but it will receive a null stream (silence/no data). This prevents the app from crashing while keeping your audio secure.
If you want to be certain that no software—Copilot or otherwise—can access the microphone, you can disable it at the driver level. Right-click the Start button and select Device Manager. Expand Audio inputs and outputs. Right-click your Microphone and select Disable device. Keep the Privacy settings for the Camera app enabled. The app will initialize successfully because the software permission is granted, but it will find no hardware to pull audio from.
You can consult the following article for more information regarding your concerns.
Hope the above information is helpful! If it is. Free feel to hit "Accepted" for benefitting others in community having the same issue too.