For me it didn't work , it was related to a path problem happened after android studio 2.0 preview 1, I needed to update genymotion and virtual box, and apparently they tried to use same port for adb.
Solution is explained here link!
Basically you just need to:
1) open genymotion settings
2) specify sdk path for the adb manually
3) adb kill-server
4) adb start-server
