I found that calling OpcCom.Interop.CreateInstance repeatedly causes a memory leak.

The following allocated memory does not get released upon leaving CreateInstance method:

Code:

GCHandle hClsid = GCHandle.Alloc(IID_IUnknown, GCHandleType.Pinned);

Adding the following code in the finally block will dealloate the memory:

Code:

if (hClsid.IsAllocated)
{
hClsid.Free();
}

brian