android studio: release apk is not signed
<p><strong>* I have rephrased the post since originally posted *</strong></p>

<p>When I try to run a just-built release apk, I get an error "the apk for your currently selected variant ... is not signed."  This is in the Edit Configuration popup.  Here are my steps:</p>

<ol>
<li>In the Build Variants tab, select "release"</li>
<li>In the menu, choose Build -> Generate Signed APK</li>
<li>In the popup, fill in the fields for the key store and passwords.</li>
<li>In the second panel, change the destination folder to ...\app\build\outputs\apk (see note * below)</li>
<li>Observe notification in upper right of studio: APK(s) generated successfully.</li>
<li>In the menu, click Run -> Run App.</li>
<li>I get an "Edit configuration" popup with the error "The apk for your currently selected variant ... is not signed.</li>
</ol>

<p>So, why this error?  The APK generated appears to be valid.  I have successfully posted it to the Android Store (alpha testing only) and verified that stack dumps are obfuscated.  </p>

<p>What I can't do is download it (step 6 above) to my device.  I guess that's ok since I can download the debug version just fine.</p>

<p>(*) Android Studio defaults the output for the release apk to a higher, presumably more convenient directory.  However I find it harder to manage the consistency of generated files when they are scattered about so I prefer all the generated apks in one place.</p>