adb server is out of date. killing... cannot bind 'tcp:5037' ADB server didn't ACK * failed to start daemon * in ubuntu 14.04 LTS

You need to set the path of your SDK's adb into Genymotion. By default, Genymotion uses its own ADB tool (for many reasons). If the both binaries are not compatible (if your Android SDK platform tools or Genymotion has not been updated for a while) this problem happens.

To solve it you can define a specific one from the Android SDK. To specify a custom ADB tool:

  1. Open Genymotion > Settings > ADB.
  2. Check Use custom Android SDK tools.
  3. Specify the path to the Android SDK by clicking Browse.
  4. Click OK.

update the adb to 1.0.32 if you have 1.0.31 or lower

adb version
Android Debug Bridge version 1.0.31
wget -O - https://skia.googlesource.com/skia/+archive/cd048d18e0b81338c1a04b9749a00444597df394/platform_tools/android/bin/linux.tar.gz | tar -zxvf - adb
sudo mv adb /usr/bin/adb
sudo chmod +x /usr/bin/adb
adb version
Android Debug Bridge version 1.0.32

for me the problem was that I am trying to use 2 adb processes

sudo apt-get remove adb android-tools-adb android-tools-fastboot

then go to your sdk and run ./adb start-server