Current versions of Microsoft Outlook for Mac apparently ship with another annoying bug. This time you can't change the font while composing an email. Complaints are piling up online, and there's no reliable fix yet. If you just want to send a code snippet in a different typeface, that's turned into a test of patience.
What exactly happens
The first reports surfaced back in mid-June. After updating to Outlook for Mac 16.110, users found that font changes were simply ignored when writing or replying to emails. Outlook shows the name of the new font after you switch, but the text still appears in the default font set in preferences, in one case Arial. Reinstalling or resetting fonts through Outlook's settings didn't help either.
The cause appears to be an encoding error in the HTML that Outlook generates. One user examined the code and found incorrectly encoded quotation marks in the font-family declaration of affected emails. That's exactly what stops the browser or mail client from applying the intended font at all.
For now, only a downgrade helps
One commenter reported on July 7 that the issue was fixed in version 16.110.3, released that same day. Other users disagree and still see the problem after the update. A moderator in Microsoft's forum confirmed that the bug can be reproduced with the latest version.
The moderator recommends that affected users contact Microsoft support and, if possible, wait for the expected version 16.112, which should include a fix. If you urgently need to switch between fonts in the meantime, downgrading to version 16.109 helps. You'll find an overview of all available Outlook versions with download links on Microsoft's website.