title: Error:Execution failed for task ':app:validateExternalOverrideSigning'
body: <p>I am using caldroid library for calendar activity and It works fine.</p>
  
  <p>But I needed to change it's style.</p>
  
  <p>So I added caldroid library(directory) under the application like this.</p>
  
  <p><img src="https://i.stack.imgur.com/xGS5A.png" alt="enter image description here"></p>
  
  <p>and I changed my dependencies </p>
  
  <blockquote>
    <p>dependencies {
       ...
        compile 'com.roomorama:caldroid:2.3.1'
       ...
    }</p>
  </blockquote>
  
  <p>to </p>
  
  <blockquote>
    <p>dependencies {
       ...
        compile project(':libraries:caldroid')
       ...
    }</p>
  </blockquote>
  
  <p>Then, It works fine under the debug mode.</p>
  
  <p>But I can't generate signed APK because of this message. </p>
  
  <blockquote>
    <p>Error:Execution failed for task ':app:validateExternalOverrideSigning'.
    Keystore file /Users/xxxxxxx.android.keystore not found for signing config 'externalOverride'.</p>
  </blockquote>
  
  <p>Is there any solution about this error?</p>