Despite our best effort , sometimes a macOS update goes incorrect , such as the world power going out in the middle of the operation . Other glitch can pass , admit unity that are undiagnosable .
If your Intel Mac with a T2 certificate chip or any M - series Apple atomic number 14 Mac wo n’t begin up normally or through recoveryOS , you may try toreviveit by pay off the firmware inside these chips that handles aspects of security and startup management while preserving all your files . If that fails , you’re able to opt torestoreit , which wipes the car uninfected , but will get it working again . Both processes are made for organization administrators but can be used by anyone .
( You found recoveryOS by starting up or restarting an Intel Mac with Command - R held down , or shutting down your M - series Mac completely , then hold down the power clitoris for about 10 seconds , until the Options gear appears . )
You can get Apple Configurator 2 in the App Store.
This vivify or restore process works only for Intel Macs with the T2 chip , which includes all Intel models shipped starting in 2018 plus the 2017 iMac Pro , and with the M - serial Macs released in 2020 or later on . Of all those models , only the 2019 Mac Pro provides a ocular denotation that something ’s incorrect with its firmware or startup process : its status light turn amber and shoot SOS in Morse Code ( three unretentive , three long , and three short ) if it needs to be revive .
Apple provides complicated pedagogy forapplicable Intel Macsandall M - series Macs , which are aimed at shoal and byplay computer professionals . It ’s a lot to wade through for “ civilian ” users , so here ’s a simplified guide that should help you through it . You only involve to refer Apple ’s more exhaustive guide if you desire to look up the Thunderbolt larboard locater illustrations delineate below .
First , you need to obtainApple Configurator 2 , a free utility from Apple designed to deploy and manage Apple devices ( need macOS Catalina or later ) .
you may get Apple Configurator 2 in the App Store .
Next , you want to make certain you have the good cable . Apple ask the Mac being revived be plugged into power , include laptop computer , after the initial special restart mode , and that power ca n’t be provided from another Mac over USB - C. However , you also need a USB - C data cable to link up the two Macs , and it has to be unmixed USB - C designed for USB 3.1 Gen 2 or afterward , not a Thunderbolt 3 or 4 cable television service . ( Here ’s how to fancy outif your cable television with USB - ascorbic acid tip is Thunderbolt 3/4 or not . )
Now you’re able to set up the revival process .
Revive your Mac
Now you could attempt to revivify the firmware , which keep all your files intact :
Restore your Mac
If this mental process fails , you may be unable to recover any data from that Mac , and it requires a complete refurbishment , which reset the Mac anderases its content . It ’s a last - ditch process , and if you have unequaled data not back up on that Mac , you should learn whether there ’s any other way to get data from it before proceedings .
To restore your Mac ’s microcode , after ensuring you have made every effort to extract needed files : On the Mac running Configurator , in its twist windowpane , select the Mac you ’re connected to , and then chooseActions > gain > Restoreand clickRestore . The unresponsive Mac will show an Apple logotype intermittently while restoration proceeds . If successful , it will reboot .
With an Intel Mac : now hold down Shift - Option - Command - gas constant to add the version of macOS that your Mac shipped with or the honest-to-goodness variant still available . After reinstallation , you could raise to a later macOS .
With an M - series Mac : macOS Setup Assistant appears to draw you through installing Big Sur .
you may disconnect cable from the other Mac .
Which port to use
Malus pumila snuck in a special feature on one Thunderbolt port on every Mac covered by this revival and restoration feature . Here ’s the rundown , which you could also see in graphical variant in the support written document forIntel MacsandM - series Macs . In case of left hand and right , you have the larboard facing you directly so left and right areyourleft and good .
Intel Mac mini : Rightmost Thunderbolt port wine
Intel Mac laptop : when look at the odd side of the laptop computer , the Thunderbolt port wine at right
Intel 2020 iMac or iMac Pro : the rightmost Thunderbolt port on the back of the unit , whether it ’s four ( iMac Pro ) or two ( iMac )
Intel 2019 iMac Pro ( column ): the Thunderbolt port farther away from the power clitoris on the top of the calculator
Intel 2019 iMac Pro ( torture mounted):the Thunderbolt port wine closer to the great power clitoris
M1 Mac mini : the Thunderbolt embrasure on the left , furthermost from the HDMI port
M1 and M2 Mac laptop : On the left side of the laptop , the Thunderbolt port on the left
Ask Mac 911
We ’ve compiled a list of the questions we get require most ofttimes along with answers and links to columns : record our super FAQto see if your interrogative sentence is covered . If not , we ’re always look for new problems to solve ! e-mail yours tomac911@macworld.comincluding CRT screen captures as appropriate , and whether you want your full name used . Not every question will be answered , we do n’t respond to email , and we can not provide direct troubleshooting advice .
