Editing Mac OS 9 (section)

==Mac OS 9 and other Mac computers==
Beginning in January 2002, Mac OS X has been set as the default operating system for all Macs produced from that point forward beginning with [[Mac OS X 10.1#Release history|10.1.2]], displacing Mac OS 9.<ref name=macosxdefault>{{cite press release|title=Apple Makes Mac OS X the Default Operating System on All Macs|url=https://www.apple.com/newsroom/2002/01/07Apple-Makes-Mac-OS-X-the-Default-Operating-System-on-All-Macs|date=January 7, 2002|publisher=[[Apple Inc.]]|access-date=April 9, 2025|archive-date=September 19, 2022|archive-url=https://web.archive.org/web/20220919180048/https://www.apple.com/newsroom/2002/01/07Apple-Makes-Mac-OS-X-the-Default-Operating-System-on-All-Macs/|url-status=live}}</ref> Despite this, Mac OS 9 continued to be preinstalled on some Macs (especially for Macs equipped with a PowerPC G4 processor) even as late as 2004, despite having its development stopped in late 2001. These Macs, despite coming with Mac OS X by default, also had Mac OS 9 preinstalled alongside the former to allow one to boot into Mac OS 9 natively if the user chooses to do so,<ref name=macosxdefault /> and allows the ability to run Classic Mac OS applications natively without resorting to the [[Classic environment]] in Mac OS X. This is especially important for applications that can directly access the computer's hardware, as well as for some applications that may have issues when running on the Classic environment. Most G4 Macs made prior to 2003 had both operating systems preinstalled alongside each other in a [[dual-boot]] configuration (with Mac OS X being selected as the default option), where they can be accessed via a boot menu accessible upon startup.

Some Macs that were released with higher CPU clock speeds (i.e. 1&nbsp;GHz or higher) are also capable of running Mac OS 9. This includes the 867&nbsp;MHz—1.25&nbsp;GHz '''"Mirrored Drive Doors"''' [[Power Mac G4]] and the 867&nbsp;MHz—1&nbsp;GHz '''"Antimony"''' titanium [[PowerBook G4]] ("TiBook"), which were released in August 2002 and November 2002 respectively. The "Antimony" titanium PowerBook G4 in particular was the last PowerBook model that came with Mac OS 9 preinstalled alongside Mac OS X, as later models only came with Mac OS X. Despite having G4 processors with faster clock speeds of up to 1.25&nbsp;GHz and 1&nbsp;GHz respectively on some models (with some Power Mac G4 models even having dual G4 processors as well), they were able to run Mac OS 9 without any issues.

The majority of Macs released in 2003 onwards only came preinstalled with Mac OS X and are incapable of booting into Mac OS 9. Most G4 Macs released during this period that have a 1&nbsp;GHz or higher processor never had their "Mac OS ROM" boot files updated to allow those Macs to officially boot into Mac OS 9 natively outside of the Classic environment. Macs equipped with a PowerPC G5 processor are unable to boot into Mac OS 9 natively because support for PowerPC G5 processors is absent on Mac OS 9 (Mac OS 9 only supports G3 and G4 processors as of Mac OS 9.2.2). The only options for running Mac OS 9 (and therefore Classic Mac OS applications) on G5 Macs is the Classic environment in Mac OS X as well as other emulation software such as SheepShaver.

The last Macs released that had Mac OS 9 preinstalled was a rerelease of the 2002 "Mirrored Drive Doors" Power Mac G4 in June 2003, which was launched around the same time as the [[Power Mac G5]] due to a perceived demand for Mac OS 9 machines. This model ended up as being one of the last Mac models overall to officially boot into Mac OS 9, making the Power Mac G4 series the last Macintosh computer to come preinstalled with Mac OS 9 after the introduction of Mac OS X. Production of this model (as well as the original version of the Power Mac G5 from 2003) was discontinued in June 2004, a year after its rerelease, which was three years after Mac OS 9 stopped development in late 2001 and two years after Mac OS X displaced Mac OS 9 as the default operating system in early 2002.

In recent years, unofficial patches have been made for Mac OS 9 and the "Mac OS ROM" to allow unsupported G4 Macs to boot into Mac OS 9 natively; this practice is not officially supported by Apple.<ref>{{Cite web |title=Mac OS 9 booting on: Previously Unspported G4 Models (Summary "Current state") |url=http://macos9lives.com/smforum/index.php/topic,4366.0.html |access-date=2021-06-11 |archive-date=2021-06-11 |archive-url=https://web.archive.org/web/20210611035726/http://macos9lives.com/smforum/index.php/topic,4366.0.html |url-status=live }}</ref>