I use flexible sub-assemblies with multiple configurations to represent various motion positions.  Very often, when I open the top level assembly the constraints will be broken.  If I edit the flexible sub-assembly in-place, and conduct a rebuild, the broken constraints will be repaired. 

Additionally, I use configurations for parts, but the configurations often switch away from the one intended within an assembly.

These two issues have increased dramatically since I installed SW2015.  I do have work arounds, but I am spending ever increasing amounts of time repairing broken constraints as the designs become larger and more complex.

(I did get hoodwinked into Windows "upgrading" to 10 Pro,,, I have applied the patch,,)

I'm curious if these problems are popping up for other users.

Windows 10 Pro

Dell Precision T1600

Intel Xeon CPU E31270 @3.40GHz

Ram 8 GB

64-bit OS, x64-based processor

ATI FirePro V4800

Driver Vers; 15.201.2401.0