According to Apple, the macOS Catalina 10.15.4 supplemental update is designed to improve the “stability, reliability, and security of your Mac”, as well as introduce some specific fixes for the issues created by the 10.15.4 update in late March. That earlier update had issues such as random reboots overnight, failures to wake up from sleep mode, unresponsive USB-C ports, kernel panic glitches and even system crashes when users attempt to make large file transfers. While the supplemental update was meant to resolve issues created by the 10.15.4 update, it is now causing even bigger problems. “The 8 April 2020 Supplemental Update for Catalina 10.15.4 brought the system down for a few hours. Since the screen only showed a white apple on the screen for the whole time I shut it down and restarted it. I got a thick white circle with a thick white line through it in the middle of the screen, the same size as the apple usually is. Repeated shut downs did nothing,” wrote one user on Apple’s own discussion forum. “WARNING macOS Catalina 10.15.4 Supplemental Update BRICKED my 13-inch Macbook 2018!” posted another user on MacRumors’ forums. “This bricked my 2019 MBP. Not providing power to devices either. Needs an SMC reset but won’t accept it,” posted a third. “Be afraid, be very afraid. Timing couldn’t be more brutal.” One member on Apple Insider’s forum said the update wrecked their desktop PC, “Yeah, this one borked my 2012 iMac. Had to reinstall from recovery. Proceed with caution.”
— russanov (@russanov) April 4, 2020
— Stephen Hackett (@ismh) March 27, 2020
— Hitoshi Harada (@umitanuki) April 4, 2020
— Abbas Jaffar Ali (@ajaffarali) April 5, 2020
Fix For macOS Catalina 10.15.4 Supplemental Update problems:
As we can see above, the problems are currently faced by those Mac owners who have downloaded the supplemental update. In order to avoid such problems, it is advisable not to install the Supplemental Update for Catalina 10.15.4 until Apple issues a fix in the future patch. For those who have already installed the supplemental update and your system is stuck or hung, there is a workaround for these issues as posted by one user on Apple’s discussions forums. “I went to Recovery Mode, ran the Disk Utilities First Aid and then rebooted again,” tim01 posted. “My screen came up and I was able to sign in.”
