title: can not build unity suddenly
body: <blockquote>
    <p>CommandInvokationFailure: Failed to build apk. See the Console for
    details. C:\Program Files\Java\jdk1.8.0_77\bin\java.exe -Xmx2048M -<br>
           Dcom.android.sdkmanager.toolsdir="C:/Users/fluentp/AppData/Local/Android/sdk\tools"
    -Dfile.encoding=UTF8 -jar "C:\Program Files\Unity\Editor\Data\PlaybackEngines\AndroidPlayer/Tools\sdktools.jar"</p>
    
    <p>stderr[
        Error: Unable to read 'D:\Project\FacebookLogin\Facebook\debug.keystore'
        Error: Keystore was tampered with, or password was incorrect
        ]
        stdout[</p>
    
    <p>UnityEditor.Android.Command.Run (System.Diagnostics.ProcessStartInfo
    psi,     UnityEditor.Android.WaitingForProcessToExit
    waitingForProcessToExit, System.String errorMsg)
        UnityEditor.Android.AndroidSDKTools.RunCommandInternal (System.String javaExe, System.String sdkToolsDir, System.String[]
    sdkToolCommand, Int32 memoryMB, System.String workingdir,
    UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit,
    System.String errorMsg)
        UnityEditor.Android.AndroidSDKTools.RunCommandSafe (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand,
    Int32 memoryMB, System.String workingdir,
    UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit,
    System.String errorMsg) UnityEditor.HostView:OnGUI()</p>
  </blockquote>
  
  <p>this is the error message on the unity console; 
  it worked well ... but suddenly made out errors on the console... when i tried to build... 
  please help me... </p>