APFS BootROM Support: If you have a machine that supports High Sierra natively, you MUST ensure you have the latest version of the system's BootROM installed. If you have NOT previously installed High Sierra, you can download and install this package (if running OS X 10.10 Yosemite or later) to install the latest BootROM version (you MUST reboot after installing the package to apply the firmware update). When installing, ensure your system is plugged in to power, or the update will not be installed.
Early-2008 or newer Mac Pro, iMac, or MacBook Pro:
MacPro3,1
MacPro4,1
MacPro5,1
iMac8,1
iMac9,1
iMac10,x
iMac11,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Catalina.)
iMac12,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Catalina.)
MacBookPro4,1
MacBookPro5,x
MacBookPro6,x
MacBookPro7,x
MacBookPro8,x
Late-2008 or newer MacBook Air or Aluminum Unibody MacBook:
MacBookAir2,1
MacBookAir3,x
MacBookAir4,x
MacBook5,1
Early-2009 or newer Mac Mini or white MacBook:
Macmini3,1
Macmini4,1
Macmini5,x (systems with AMD Radeon HD 6xxx series GPUs will be almost unusable when running Catalina.)
MacBook5,2
MacBook6,1
MacBook7,1
Early-2008 or newer Xserve:
Xserve2,1
Xserve3,1
Machines that ARE NOT supported:
2006-2007 Mac Pros, iMacs, MacBook Pros, and Mac Minis:
MacPro1,1
MacPro2,1
iMac4,1
iMac5,x
iMac6,1
iMac7,1
MacBookPro1,1
MacBookPro2,1
MacBookPro3,1
Macmini1,1
Macmini2,1
— The 2007 iMac 7,1 is compatible if the CPU is upgraded to a Penryn-based Core 2 Duo, such as a T9300.
2006-2008 MacBooks:
MacBook1,1
MacBook2,1
MacBook3,1
MacBook4,1
2008 MacBook Air (MacBookAir 1,1)
AMD/ATI Radeon HD 5xxx and 6xxx series graphics acceleration: Currently, it is not possible to achieve full graphics acceleration under Catalina on any machines that use a Radeon HD 5xxx or 6xxx series GPU. If you have a machine with one of these GPUs installed, I'd advise upgrading it if possible (can be done in 2010/2011 iMacs, iMac11,x-12,x), disabling the dedicated GPU if using a 2011 15" or 17" MacBook Pro (MacBookPro8,2/8,3, instructions to do so can be found here), or not installing Catalina. Running Catalina without full graphics acceleration will result in extremely poor system performance.
2008 Mac Pro 3,1 AMD GPU Support: FIXED as of Catalina Patcher 1.2.0.
I get an error saying "The installer is damaged, and can't be used to install macOS"
This happens when using a release of the macOS Catalina Installer App that is incompatible with the version of Catalina Patcher you are using. Download the latest Catalina Installer using the latest Catalina Patcher version.
Some third-party applications do not open or crash on launch
This is an issue Apple introduced in 10.15.4, and is not an issue with the patch itself. To work around this, immediately relaunch the affected application after receiving the crash message. After that point, the affected application should no longer experience this crash.
During installation, the machine keeps booting off the installer volume, and will not complete the second phase of installation
This usually occurs on machines that support High Sierra (macOS 10.13) natively, but whose owners have not installed High Sierra on them previously. Installing High Sierra on these machines will update the machine's system firmware, allowing it to boot from an APFS volume. This is necessary in order to boot Catalina. Please follow the instructions in the "Important Info" section above to rectify.
During installation, the installer reports that "An error occurred during installation", and mentions running diagnostics
This occurs when the copy of the macOS Catalina Installer app used has gotten corrupted somehow. To rectify this, use Catalina Patcher to download a fresh copy of the Catalina installer, then re-create an installer volume and/or retry the installation.
The Zoom application does not show any video during meetings
This is due to the latest Zoom versions requiring a Metal-compatible GPU for video rendering. To patch this out of the Zoom application, download and run the script located here, or here for later Zoom versions.