Short Version:
Board: STM32F407vet6 - Black Edition: http://wiki.stm32duino.com/index.php?title=STM32F407
Cores Generic (limited Support for STM32F4): https://github.com/danieleff/STM32GENERIC : Runs on Arduino IDE and VM
Cores of Stevstrong (better Support for STM32F4): https://github.com/stevstrong/Arduino_STM32/ : Runs at Arduino IDE, not at VM. (Hopefully) relevant verbose messages:

[...]
_f407v\Debug\core\syscalls.c.o"
[...]
"arm-none-eabi-g++*: error: f407v\Debug\core\libmaple\syscalls.c.o: No such file or directory"
 

---

Long (er) version:
Hi,
you wan't to read more? Also in "not so good english"? Let's do:
I have a STM32F407vet6 Board (all links in short Version). It runs with the STM32Generic-Cores in the Arduino IDE and VisualMicro without Problems. But the STM32 generic cores are designed for the F1 boards and have only limited support for the F4 boards. But since I needed some special functions of the F4 board (RTC,..), I need the STM32 cores from stevstrong.
These works in the ArduinoIDE fine. But VisualMicro has problems with it. I have asked the developer stevestrong, but he can't help me more, because he doesn't work with VisualMicro.
The verbose messages indicate that VisualMicro moves compiled core files to the wrong folder, or searches in the wrong folder (quote above).
How i can change that?

Thanks for reading and thinking!
da_user

Hi,
sorry, no doesn't work. Same Error. I had installed the update and specially testet with a new Project.
Full Verbose on Pastebin: https://pastebin.com/k0qVnz1U