I very strangely found the same error. The other answer is a workaround not a direct answer. In my case the solution was to initialize MemoryPreference = MediaCaptureMemoryPreference.Cpu in the MediaCaptureInitializationSettings passed to InitializeAsync. I think the issue lay that it used GPU memory by default which made the SoftwareBitmap unavailable. Why there is not better documentation as to the necessity of this, or an example showing how to move the GPU memory to CPU is beyond me.