We use Slack at Evergreen to chat amongst our team—like pretty much everybody else in the world these days—and I like to use the web app versus installing a desktop app, because it works great and keeps things in one browser.

Among many of Slack’s settings are notification sounds you can choose from. I picked one that I liked: a simple but pleasant ding, and got back to work. When the first notification hit, it was bizarre. I could hear the ding, but it was in the midst of a cacophony coming through my headphones. There was a much different notification sound happening at the same time.

It turns out that web desktop notification support is built into the computer’s operating system. Not only was I getting Slack’s notification, I was also getting the notification set for Firefox at the same time.

Fixing the problem is easy, but there is a caveat.

  1. Open up System Preferences
  2. Click on Notifications in the top right corner.
  3. Choose Firefox.
  4. Uncheck “Play sound for notifications”

The caveat is that you’re disabling the sound for all notifications coming from your browser. That means other non-Slack notifications will also fall silent. I don’t mind, because Slack is the only web app I use that uses these alerts. If you use more than that, you may want to go the opposite route and turn off notification sounds in Slack instead.