No opens from Office 365 Recipients


There are two organizations that I email who use Office 365 (with desktop client). Each of them, do not reveal to me when they have opened one of my emails. No other recipients have this issue, including when I use my Webmail to accidentally trigger a false positive hit on the open-tracking from Mailspring. This is very irritating too btw.

To Reproduce…

Steps to reproduce the behavior:

  1. Send an email to a recipient with Office 365.
  2. Have the recipient open the email (I can only confirm that it happens with the Outlook Desktop App, I’m not sure if it occurs with webmail client).
  3. Verify that Mailspring does not register any opens “No opens”.
  4. Wait some time, try with multiple Mailspring clients even, verify again.
    (You can even wait for that person to reply, still no “opens” will register).

Expected Behavior

I expect it to accurately reflect when the email has opened…


I don’t see an attachment feature on here, but there also is not much point.


  • OS and Version: Linux Mint 20.3 and Windows 11
    • Installation Method: .deb and .exe
  • Mailspring Version: 1.9.2-6e14dad1

The feature allowing to report whether e-mail was opened is voluntary on the recipients side, but quite often banned and filtered by large organisations.

Don’t expect miracles here.