HTML Help Workshop returns error after successfully compiled .chm file
<p>I'm facing a quite weird failure after I successfully compiled a .chm file with <em>HTML Help Workshop</em>'s <code>hhc.exe</code>. </p>

<p>I created a documentation of my source code with <em>Doxygen</em>. <em>Doxygen</em> creates if you enable <code>GENERATE_HTMLHELP</code> in the doxygen file:</p>

<blockquote>
  <p>If the GENERATE_HTMLHELP tag is set to YES then doxygen generates three<br>
  additional HTML index files: index.hhp, index.hhc, and index.hhk. The  index.hhp<br>
  is a project file that can be read by Microsoft's HTML Help Workshop (see:<br>
  <a href="http://www.microsoft.com/en-us/download/details.aspx?id=21138" rel="nofollow noreferrer">http://www.microsoft.com/en-us/download/details.aspx?id=21138</a>) on Windows.</p>
</blockquote>

<p>After <em>Doxygen</em> creates those files, I want to create the .chm file with <em>HTML Help Workshop</em>. For that reason I call <code>hhc.exe</code> in a CMD. After that I can open the .chm file and everything seems fine. But if I ask the CMD for the current <code>errorlevel</code>, it outputs:</p>

<pre><code>"C:\Program Files (x86)\HTML Help Workshop\hhc.exe" index.hhp
Microsoft HTML Help Compiler 4.74.8702

Compiling C:\... folder path ...\index.chm

Compile time: 0 minutes, 0 seconds
37      Topics
346     Local links
12      Internet links
0       Graphics

Created C:\... folder path ...\index.chm, 88,740 bytes
Compression decreased file by 194,682 bytes.

echo %errorlevel%
1
</code></pre>

<p>Does anyone have an idea of what the h... is going wrong here and how I can avoid that problem that it's compiled successfully but still returns an error? How can I figure out what's the problem instead of an error "1"?</p>

<p>The problem is that my build server (TFS2015) returns the error and the build is failed.</p>