Seeing flaky behaviour with these tools but the other engineers around me have grown to just accept that this is normal behaviour. Being new, I haven't yet!
The debugger bales out more than 50% of the time, with "No Ulink device found", followed by "Error: Flash Download failed - Target DLL has been cancelled". However , In configure Flash Tools, Utilites tab, Setting button, the Programming algorithm is set to match my target device, STM32F4xx Flash and works when it feels like it, so it can't be that its not been set up correctly in the frist place.
The Ulink appears & disappears in device manager OK, and is correctly id'd. Its driver v1.0.0.3.
The problem can be circumvented by killing the debugger, disconnecting the USB & power cycling the target, but come on, Keil, what is the problem here? It even loses the connection is it sits idle for a few minutes!