Do I need to use the CRT for Memory Validator to detect memory leaks?
No. Memory Validator inspects all Win32 heaps (HeapCreate etc), the GlobalAlloc() heap, LocalAlloc() heap, CoTaskMemAlloc() heap, IMallocSpy, as well as the C runtime heap(CRT). If you are using any of these heaps Memory Validator is capable of monitoring the memory allocations and deallocations. If you are using a custom heap manager of your own design (or a 3rd party design) you can provide Memory Validator with information via the API so that Memory Validator can track the behaviour of your custom heap manager.