The Microsoft Sound is the startup sound for the Windows 95 operating system. It was composed by the English musician Brian Eno and commissioned as a seconds-long piece of music intended to evoke emotion. In 2025, the Microsoft Sound was selected for preservation in the US National Recording Registry by the Library of Congress. That year, Eno donated his fee to non-profit organisations and coalitions supporting Palestine or peace after accusing Microsoft of complicity in Israeli war crimes in the Gaza war.
In 1994, the Microsoft designers Mark Malamud and Erik Gavriluk approached Eno to compose music for the operating system Windows 95. According to Eno: "The thing from the agency said, 'We want a piece of music that is inspiring, universal, blah-blah, da-da-da, optimistic, futuristic, sentimental, emotional,' this whole list of adjectives, and then at the bottom it said 'and it must be three-and-a-quarter seconds long'. I thought this was so funny and an amazing thought to actually try to make a little piece of music. It's like making a tiny little jewel."
At the time, Eno was struggling to create music and appreciated the challenge of a specific problem. He "got completely into this world of tiny, tiny little pieces of music" and created 84 compositions. He used a Macintosh to create the sound as he did not like PCs. The final composition was six seconds long. GQ described it as "a blossom of piano, bells, and hums that evokes the sun peeking from behind a storm cloud". Afterwards, Eno was creatively unblocked and found that full-length compositions seemed "like oceans of time". He was paid $35,000 for the composition.

Pitchfork suggested the Microsoft Sound was one of the most frequently heard pieces of music in North America. In April 2025, it was selected for preservation in the US National Recording Registry by the Library of Congress as "culturally, historically or aesthetically significant".
In May 2025, Eno wrote an open letter to Microsoft accusing it of complicity in Israeli war crimes in the Gaza war for providing Israel with AI and cloud services. He wrote: "Millions — possibly even billions — of people have since heard that short start-up chime — which represented a gateway to a promising technological future ... I never would have believed that the same company could one day be implicated in the machinery of oppression and war ... My new start-up chime is this: stand in solidarity with the brave Microsoft workers who have done something truly disruptive and refused to stay silent."
In an interview with GQ, Eno said: "That’s the most shattering thing about it—the disappointment of the utopianism I remember so well from the '80s and '90s. These awful, dodgy companies seem to be only motivated by money." He donated his fee, which he adjusted to $80,000 for inflation and rounded up to $100,000, to three non-profit organisations and coalitions supporting Palestine or peace, including the Stop the War Coalition and medical services.