<p dir="auto">When installing on Windows 7 x64 with:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="pip install opencv-python     # py 2.7"><pre class="notranslate"><code class="notranslate">pip install opencv-python     # py 2.7
</code></pre></div>
<p dir="auto">or</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="pip3 install opencv-python     # py 3.6"><pre class="notranslate"><code class="notranslate">pip3 install opencv-python     # py 3.6
</code></pre></div>
<p dir="auto">in both cases, it installs succesfully but at the end, when doing:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="import cv2"><pre class="notranslate"><code class="notranslate">import cv2
</code></pre></div>
<p dir="auto">we have this bug:</p>
<blockquote>
<p dir="auto">ImportError: DLL load failed: The specified module could not be found.</p>
</blockquote>
<p dir="auto">As noted <a href="https://github.com/skvark/opencv-python/issues/114" data-hovercard-type="issue" data-hovercard-url="/opencv/opencv-python/issues/114/hovercard">on many posts</a>, the reason is that this file is missing:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="MS-WIN-DOWNLEVEL-SHLWAPI-L1-1-0.DLL"><pre class="notranslate"><code class="notranslate">MS-WIN-DOWNLEVEL-SHLWAPI-L1-1-0.DLL
</code></pre></div>
<p dir="auto">Fix: install KB2670838 / <a href="https://www.microsoft.com/en-us/download/details.aspx?id=36805" rel="nofollow">Platform Update for Windows 7</a>, less than 15 MB</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Windows6.1-KB2670838-x64.msu"><pre class="notranslate"><code class="notranslate">Windows6.1-KB2670838-x64.msu
</code></pre></div>
<p dir="auto"><strong>Todo: Can we put this in the release notes of Open CV 3.4.3 or better:<br>
Can we do a <code class="notranslate">try: ... except: ...</code> and display <code class="notranslate">Please install Platform Update for Windows 7 / KB2670838</code> instead of just a non-explicit <code class="notranslate">DLL load failed</code> message ?</strong></p>
<p dir="auto">It would save countless hours for Windows users trying to install OpenCV.</p>
<p dir="auto">the installed opencv_world342.dll need "Api-ms-win-downlevel-shlwapi-l1-1-0.dll" which is not in Windows 7. (vc2015_redist.exe already installed).</p>
<p dir="auto">when I copy it from windows10, it works.</p>