I've upgraded from 1.6.7 to 1.6.8 and found that a large project targeting a Mega2560 is recompiling every referenced file, every time. It used to only recompile the changed files referenced within the sketch.
I've uninstalled it, downloaded a fresh copy and reinstalled, with the same result. It's installed on 64-bit Windows 7 in C:\Arduino, and there are no spaces in the paths to any sketch or library.
Any thought, please? The slow build time is becoming a problem!