I am also facing same issue .. Don't know if appium supports Android N ( dev preview 3)
[36minfoe[39m: [debug] executing cmd: C:\SDK\platform-tools\adb.exe -s ZX1G42793T push "C:\Program Files (x86)\Appium\node_modules\appium\build\android_bootstrap\AppiumBootstrap.jar" /data/local/tmp/
e[36minfoe[39m: [debug] Pushing settings apk to device...
e[36minfoe[39m: [debug] executing cmd: C:\SDK\platform-tools\adb.exe -s ZX1G42793T install "C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk"
e[36minfoe[39m: [debug] Stopping logcat capture
e[36minfoe[39m: [debug] Logcat terminated with code null, signal SIGTERM
e[36minfoe[39m: [debug] Sent shutdown command, waiting for UiAutomator to stop...
e[33mwarne[39m: UiAutomator did not shut down fast enough, calling it gone
e[36minfoe[39m: [debug] Cleaning up android objects
e[36minfoe[39m: [debug] Cleaning up appium session
e[31merrore[39m: Failed to start an Appium session, err was: Error: Command failed: C:\windows\system32\cmd.exe /s /c "C:\SDK\platform-tools\adb.exe -s ZX1G42793T install "C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk""
Failed to install C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk: Failure [INSTALL_FAILED_ALREADY_EXISTS: Attempt to re-install io.appium.settings without first uninstalling.]
e[36minfoe[39m: [debug] Error: Command failed: C:\windows\system32\cmd.exe /s /c "C:\SDK\platform-tools\adb.exe -s ZX1G42793T install "C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk""
Failed to install C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk: Failure [INSTALL_FAILED_ALREADY_EXISTS: Attempt to re-install io.appium.settings without first uninstalling.]
at ChildProcess.exithandler (child_process.js:751:12)
at ChildProcess.emit (events.js:110:17)
at maybeClose (child_process.js:1016:16)
at Process.ChildProcess._handle.onexit (child_process.js:1088:5)
e[36minfoe[39m: [debug] Responding to client with error: {"status":33,"value":{"message":"A new session could not be created. (Original error: Command failed: C:\windows\system32\cmd.exe /s /c \"C:\SDK\platform-tools\adb.exe -s ZX1G42793T install \"C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk\"\"\nFailed to install C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk: Failure [INSTALL_FAILED_ALREADY_EXISTS: Attempt to re-install io.appium.settings without first uninstalling.]\r\n)","killed":false,"code":1,"signal":null,"cmd":"C:\windows\system32\cmd.exe /s /c \"C:\SDK\platform-tools\adb.exe -s ZX1G42793T install \"C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk\"\"","origValue":"Command failed: C:\windows\system32\cmd.exe /s /c \"C:\SDK\platform-tools\adb.exe -s ZX1G42793T install \"C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk\"\"\nFailed to install C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk: Failure [INSTALL_FAILED_ALREADY_EXISTS: Attempt to re-install io.appium.settings without first uninstalling.]\r\n"},"sessionId":null}
e[36minfoe[39m: e[37m<-- POST /wd/hub/session e[39me[31m500e[39me[90m 10917.838 ms - 1261e[39m e[90me[39m
Exception in thread "main" org.openqa.selenium.SessionNotCreatedException: A new session could not be created. (Original error: Command failed: C:\windows\system32\cmd.exe /s /c "C:\SDK\platform-tools\adb.exe -s ZX1G42793T install "C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk""
Failed to install C:\Program Files (x86)\Appium\node_modules\appium\build\settings_apk\settings_apk-debug.apk: Failure [INSTALL_FAILED_ALREADY_EXISTS: Attempt to re-install io.appium.settings without first uninstalling.]
) (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 11.19 seconds
Build info: version: '2.53.0', revision: '35ae25b', time: '2016-03-15 17:00:58'
Driver info: io.appium.java_client.android.AndroidDriver
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:206)
at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:158)
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:678)
at io.appium.java_client.DefaultGenericMobileDriver.execute(DefaultGenericMobileDriver.java:43)
at io.appium.java_client.AppiumDriver.execute(AppiumDriver.java:1)
at io.appium.java_client.android.AndroidDriver.execute(AndroidDriver.java:1)
at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:249)
at org.openqa.selenium.remote.RemoteWebDriver.(RemoteWebDriver.java:131)
at org.openqa.selenium.remote.RemoteWebDriver.(RemoteWebDriver.java:144)
at io.appium.java_client.DefaultGenericMobileDriver.(DefaultGenericMobileDriver.java:39)
at io.appium.java_client.AppiumDriver.(AppiumDriver.java:69)
at io.appium.java_client.AppiumDriver.(AppiumDriver.java:78)
at io.appium.java_client.android.AndroidDriver.(AndroidDriver.java:67)
at com.appium.fwfiles.SetUpUtilities.startServerForAllDevices(SetUpUtilities.java:205)
at com.appium.fwfiles.SetUpUtilities.startExecution(SetUpUtilities.java:416)
at com.appium.driver.AutomationDriver.main(AutomationDriver.java:27)
Picked up JAVAOPTIONS: -Djava.net.preferIPv4Stack=true