So as not to mess up my Arduino setup on my Mac I am experimenting with Windows XP in a Parallels Desktop window on the Mac. You can keep images of the XP setup for easy backup.
This will just be used for STM32 sketches
Delete all traces of old Arduino in the XP image.
Downloaded and install Arduino 1.6.1 for Windows
Downloaded the ZIP of the STM32 files found bottom right on this page
Open My Documents . . . right click New - Folder . . . name the folder Arduino
Then insert a hardware folder with the ZIP contents . . . . Arduino\hardware\Arduino_STM32
(remove Master in the ZIP name)
IMPORTANT
Start Arduino - go to File - Preferences and change the Sketchbook location folder to
\psf\Home\Documents\Arduino (as used by Parallels Desktop)
Under Tools - Board all the new STM32 boards are listed
The contributed sketches are in File - Sketchbook - hardware - Arduino_STM32
On my board BOARD_LED_PIN must be changed to PC13
To import libraries select as needed from the STM32F1 subfolder