title: hyperlink to an existing Outlook mail message
body: <p>In Outlook 2016, I'd like the body of a mail message to include a hyperlink to another, existing mail message.</p>
  <p>The general idea is that message2 would have a link to message1, and anyone who's previously received message1 and is reading message2 could click the link to open their own copy of message1 (i.e., in their own Outlook inbox; no cross-mailbox permissions needed; link would only try to access the clicker's own inbox).</p>
  <p>I know that setting the href to &quot;outlook:ENTRYID&quot; is a possibility. (Without the quotes, and of course substituting actual entryID for that placeholder.) But the value of ENTRYID changes when the message is moved to a different folder, and anyway is unique to &quot;my&quot; mailbox (and wouldn't work for recipients of message2).</p>
  <p>And I've learned how to get the PR_SEARCH_KEY of an existing email (thanks to <a href="https://www.slipstick.com/developer/read-mapi-properties-exposed-outlooks-object-model/" rel="nofollow noreferrer">this article</a>).</p>
  <p>But an href of &quot;outlook:PR_SEARCH_KEY&quot; doesn't work / target can't be found.</p>
  <p>Finally, I've read that &quot;outlook:GUID&quot; works. But I can't figure out how (in Outlook VBA) to get the GUID of an existing email.</p>
  <p>Does anyone know how to programmatically (VBA) get the GUID? Or convert PR_SEARCH_KEY to be a GUID? Or (back to my root question) any other way to create a hyperlink to an existing Outlook mail message?</p>
  <p>The hyperlink only needs to work from within Outlook 2016 itself (so no concerns about the &quot;outlook:&quot; protocol not being recognized elsewhere on my computer).</p>
  <p>Thanks very much.</p>