Moving PT10 Project from OSX to Windows Changes Pitch/Tempo

Using PT10 on OSX, my 48khz/24-bit project is fine.



My audio interface is a MOTU PCIe + four 1224's. (running at 48khz)



However, when I copy my working project and launch it in Windows 7 (also PT10), where I am also running the MOTU audio at 48khz, the project audio plays back slower in speed, and lower in pitch.



Any ideas on how to solve?