It seems GetItemImage(handle) in debugger stack window incorrectly expects a 32-bit long handle whereas it is 64-bit on x64. Last working pywin32 version is 219 but they don't have builds for python 3.6. So I just commented line 219 (interesting coincidence!) in debugger.py and shifted next line to the left: #if self.list.GetItemImage(handle)!= (col, selCol): self.list.SetItemImage(handle, col, selCol) SetItemImage doesn't have this bug so it works fine.