<p dir="auto">Splitting off from:  <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="215152737" data-permission-text="Title is private" data-url="https://github.com/flutter/flutter/issues/8876" data-hovercard-type="issue" data-hovercard-url="/flutter/flutter/issues/8876/hovercard" href="https://github.com/flutter/flutter/issues/8876">#8876</a></p>
<p dir="auto">Just helped track down an issue an internal customer was having whereby multiple <code class="notranslate">adb</code> instances were fighting each other:</p>
<ul dir="auto">
<li><code class="notranslate">/usr/bin/adb</code> existed as part of the <code class="notranslate">adb</code> Debian package that was installed on the user's system.  It seemed to be restarting its server automatically when killed because of an entry in <code class="notranslate">init.d</code></li>
<li><code class="notranslate">$ANDROID_HOME/platform-tools/adb</code> was the user's preferred <code class="notranslate">adb</code> instance and was also the instance detected by flutter tools since it lived in a proper SDK folder structure.</li>
</ul>
<p dir="auto">There was initially an issue whereby one <code class="notranslate">adb</code> client process would detect a mismatch between the client and server versions and restart the appropriate server, and in so doing, it'd echo a message to  the terminal that flutter tools mistook for a device line (fixed in <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="225344131" data-permission-text="Title is private" data-url="https://github.com/flutter/flutter/issues/9693" data-hovercard-type="pull_request" data-hovercard-url="/flutter/flutter/pull/9693/hovercard" href="https://github.com/flutter/flutter/pull/9693">#9693</a>).</p>
<p dir="auto">Once that issue was fixed, the two <code class="notranslate">adb</code> servers still seemed to be fighting each other, causing the preferred <code class="notranslate">adb</code> to show no connected devices even though there were devices connected.  The solution we eventually found for this was uninstalling <code class="notranslate">/usr/bin/adb</code> (via <code class="notranslate">sudo apt-get remove adb</code>)...</p>
<p dir="auto">This experience, along with reports within the Flutter team of multiple <code class="notranslate">adb</code> instances not playing nicely with each other and with Flutter tools, means we probably want to add a doctor validator that will warn the user if multiple adb binaries are detected.</p>