title: OneNote Add-in greyed out in Outlook
body: <p>Want to document my discovery with enabling disabled OneNote Add-inin Outlook.<br />
  <strong>Symptoms:</strong></p>
  <ol>
  <li>In Tasks folder OneNote button was greyed out</li>
  <li>In other folders OneNote button was enabled</li>
  <li>When selecting task created from the message OneNote button was re-enabled.<br />
  <strong>Solution:</strong><br />
  I searched all the solutions which appear in <a href="https://www.google.ru/search?ie=UTF-8&amp;q=send%20to%20onenote%20greyed%20out" rel="nofollow noreferrer">https://www.google.ru/search?ie=UTF-8&amp;q=send%20to%20onenote%20greyed%20out</a>, but nothing helped. Of course, I am not taking seriously recommendations to reinstall Office or Windows.</li>
  </ol>
  <ol>
  <li>I tried to monitor Outlook.exe with procmon64.exe and found that there are calls to value in &quot;HKCU\Software\Microsoft\Office\16.0\OneNote\OneNotePreferAgaveAddin&quot; with result &quot;NAME NOT FOUND&quot;. Creating the REG_DWORD Value affected &quot;Send to OneNote&quot; button - with 1 it disappeared and with 0 appeared. But it didn't solve my problem.</li>
  <li>Then I searched for IPM.Task in the registry to find whatever settings which might influence work with Tasks in Outlook. And I found key &quot;Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\REGISTRY\MACHINE\Software\Wow6432Node\Microsoft\Office\16.0\OneNote\Outlook Add-in\Message Classes&quot; with values &quot;IPM.Note.Rpmsg.Microsoft.Voicemail.UM&quot; and &quot;IPM.Task&quot; (REG_DWORD with Data=0). After removing value IPM.Task - &quot;Send to OneNote&quot; button becomes enabled in Tasks folder/view.
  Hope, it might help others :)</li>
  </ol>