I am getting the swoosh sound in Sierra, but at the moment I cannot find where to turn it on or off. I did find a lot of complaints on the web of its being lost in El Capitan however. confused In Mail>Preferences>General there is a setting for incoming mail sounds AND below that there is a check box to enable sounds for other Mail actions. That may include the outgoing mail "swoosh".
On a Mac since 1984.
Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.
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