in the PCI-based Power Macs) use a unique chime, which is also in the television commercials for the Power Macintosh and PowerBook series from 1995 until 1998, and the 20th Anniversary Macintosh uses another unique sound. For models built prior to the introduction of the Power Macintosh in 1994, the failure of initial self-diagnostic tests results in a Sad Mac icon, an error code, and distinctive Chimes of Death sounds. The chime for all Mac computers from 1998 to early 2016 is the same chime used first in the iMac G3. The chord is a F-sharp major chord, and was produced by pitch-shifting the 840AV's sound. Since 2012, the Mac startup chime is a registered trademark in the United States, and is featured in the 2008 Pixar film WALL-E when the titular robot character is fully recharged by solar panels as well as in the 2007 Brad Paisley song "Online". Starting with the 2016 MacBook Pro, all new Macs were shipped without a startup chime, with the Macs silently booting when powered on. In 2020, the startup chime would be added to these models with the release of macOS Big Sur, which allows it to be enabled or disabled in System Preferences. On the macOS Big Sur 11.0.1 beta, it was discovered that the new lower pitched chime was brought to all older supported Macs. In a firmware update included in the macOS Catalina 2020-001 Security Update, and the macOS Mojave 2020-007 Security Update, the new startup chime in Big Sur is brought to all Big Sur-supported Macs including the unsupported 2013 iMac. Happy Mac A Happy Mac is the normal bootup (startup) icon of an Apple Macintosh computer running older versions of the Mac operating system. It was designed by Susan Kare in the 1980s, drawing inspiration from the design of the Compact Macintosh series and from the Batman character Two-Face. The icon remained unchanged until the introduction of New World ROM Macs, when it was updated to 8-bit color. The Happy Mac indicates that booting has successfully begun, whereas a Sad Mac (along with the "Chimes of Death" melody or one or more beeps) indicates a hardware problem. When a Macintosh boots into the classic Mac OS (Mac OS 9 or lower), the system will play its startup chime, the screen will turn gray, and the Happy Mac icon will appear, followed by the Mac OS splash screen