title: android app install:Re-installation failed due to different application signatures
body: <p>I build a app at one PC and then copy to another, then I run my device, tip:</p>
  
  <pre><code>Re-installation failed due to different application signatures.
  </code></pre>
  
  <p>actually, I did not sign app . unfortunately this apk I have send to my user and them update it automatically (app check version and then download and call to install), so them failed to install when update.</p>
  
  <p>my questions:</p>
  
  <ol>
  <li>I did not sign apk, but between the two computers, them sign automatically?</li>
  <li>how to fix it when I copy code between PCs?</li>
  </ol>
  
  <hr>
  
  <p>I have done following this post:
  <a href="https://stackoverflow.com/questions/2887436/re-installation-failed-due-to-different-application-signatures">enter link description here</a></p>