Episode 148 of the fabulous podcast 99% Invisible is about trademarked sounds (yes, it turns out you can do that). It's a fascinating 16 minutes on sound design.

One of the sounds mentioned is that startup chime used by Apple for the Macs. Back in the early 1990s, some people at Digital Equipment Corp. (aka DEC) wanted to add a startup chime to DEC's workstations. They thought the obvious choice was the notes for the initials: D,E,C. Sonic branding direct from the name! What could be better?

Unfortunately, D,E,C is parallel to the first three notes of the iconic theme from Steven Spielberg's Close Encounters of the Third Kind from 1977. Although the actual notes are G,A,F, F (octave lower), C, for those familiar with the movie, the D,E,C startup almost demands the completion of the sequence. Rather than a soothing, inviting soundscape as the system was booting, it created an unfulfilled tension.

As far as I know, the tones were never used in a shipping product.