WPF C# application showing very high unmanaged memory usage – how to identify root cause?

I'm currently facing an issue with very high unmanaged memory usage in my WPF C# application, and I'm struggling to identify the root cause.

From my profiling results, I can see:

Total memory used: ~ 1.45 GB Unmanaged memory: ~ 1.28 GB Managed heap (Gen 0/1/2): relatively normal LOH: ~ 62 MB

This suggests that most of the memory consumption is coming from unmanaged allocations, not the .NET managed heap.

Screenshot from profiler:

What I've tried:

Used Visual Studio Diagnostic Tools to monitor memory Checked managed heap allocations (nothing unusual) Verified no obvious large object allocations in managed code Tried forcing GC (GC.Collect()), but unmanaged memory is not released