When your Mac start acting up , you ’ll in all probability go through some common troubleshooting procedures , such as re-start it , run Disk Utility , and perhaps performing a Safe Boot . Your repair repertory should also include a duo of additional procedures that can occasionally eliminate otherwise inscrutable job — micro-cook the NVRAM and reset the SMC .
The procedures here practice to Intel - based Macs . M - Series Macs do n’t have a procedure for zapping the NVRAM , and they do n’t have an SMC . For M - series Macs , adjudicate shutting down the computer , waiting for several seconds , and then boot it .
What is PRAM?
Back in the day , the received list of quick fixes for random Mac ailment always include crystallize the stroller . The P in PRAM stand up for “ argument ” ( the RAM was just RAM — random admission memory ) , and it referred to a pocket-sized amount of particular , barrage fire - backed memory in every Mac that stored information the reckoner necessitate before it loaded the operating system . If the values in this memory get out of whack for one reasonableness or another , your Mac might not start up correctly or might exhibit any of numerous odd behaviors later . So you could press a key sequence at startup to readjust ( or “ zap ” ) the PRAM , returning it to default , mill values .
What is NVRAM?
Modern Macs no longer employ baby carriage ; they instead utilise something called NVRAM ( NV for non - explosive ) . NVRAM serves approximately the same purpose as PRAM , but instead of storing a 12 or more pieces of selective information , it now contains just a few : your selected startup magnetic disc , speaker bulk , screen resolution , time zone , and — if your Mac has doss down latterly — detail of the last kernel panic .
NVRAM putrefaction is fair uncommon , but if your Mac seems to take forever to figure out the correct boot record , begin up with the wrong silver screen resolution , or suffers from eldritch audio problems ( like there ’s no phone whatsoever or the menu bar ’s bulk controller is grayed out ) , a reset of the NVRAM might help — and it ’s quick and harmless .
When should you reset NVRAM?
If you notice that your Mac setting ceaselessly get befuddle out of whack , it might be sentence to readjust the NVRAM . For example , if you discover that your screen resolution or sound loudness never ride out at the setting you require , or the date and time are always wrong . If you notice annoying problem that do n’t get fixed by set your setting , or your options never seem to take , try readjust the NVRAM .
Is it safe to reset the NVRAM?
When you catch one’s breath the NVRAM , your Mac will return to factory default option place setting . So it ’s good in the horse sense it that it does not harm the Mac , but you might conceive of it as “ insecure ” in that any customization you ’ve done to the system options may be lost . You may have to go back and reinstate some of those scope .
How reset NRAM
M-series Macs
On M - series Macs , the NVRAM is test during the inauguration process , and if the system notice a pauperism to reset , it will . There is n’t a key combination that you bear down while starting up the Mac . If you would care the organisation to audit the NVRAM on an M - series Mac , shut it down completely , wait a few indorsement , and then power up the Mac .
Intel Macs
To readjust your NVRAM , you use incisively the same subroutine you once used to readjust PRAM .
If you hold down Command - Option - phosphorus - R at startup and you see nothing but a gray screen that does n’t interchange for several minute — no Apple logo , no progress stripe , no second inauguration gong — don’t affright . The most likely cause is that your Mac is n’t registering the key insistence due to wonkiness with a USB machine . Disconnect all USB machine ( except your keyboard , if it ’s a pumped keyboard ) , hold the mogul clitoris down until the Mac shuts off wholly , and then adjure it again and straight off hold down Command - Option - P - R.
If that does n’t work and you ’re using an external Bluetooth keyboard , try plugging in a USB keyboard instead . If you ’re able to reset the NVRAM successfully with the wired keyboard , you’re able to disconnect it and go back to your normal Bluetooth keyboard .
Terminal
More modern users can seek using the Terminal to reset to NVRAM , though if you ’ve reached this choice the trouble is likely bigger than resetting NVRAM . And as with all Terminal commands , the usual caveats use : You ’re messing with macOS ’s bash shell and could do irrevocable damage with the wrong keystroke . But if you ’d care to adjudicate , you may type the stick with instruction into a new Terminal windowpane :
After running the bidding , reset your Mac so the changes can take force .
What is SMC?
Yet another component of an Intel Mac ’s hardware that store essential options is the System Management Controller ( SMC ) . This circumference take with business leader management , temperature monitoring and fan control , status brightness level , keyboard backlights , and a few other components .
What should you rest the SMC?
If your SMC becomes befuddled , you could experience problems like excessive fan noise , tedious operation even thoughActivity Monitordoesn’t show the CPU being overtaxed , apps that take forever to establish , stamp battery that do n’t charge correctly , problems with sleep or inflame , and so on . ( you’re able to see a longer list onthis Apple support pageboy . ) As with zapping the NVRAM , resetting the SMC to manufactory default may settle these problem .
Is it safe to reset the SMC?
It is secure to reset the SMC . You should check your Battery system taste after to see if your customizations have been maintain .
How to reset the SMC
M - series Macs do n’t have a System Management Controller ( SMC ) . The procedure the SMC handled are now care by the M chip itself . Postings on Apple ’s assembly evoke keep out down an M - serial Mac completely and leaving it off for 30 seconds to perform something like an SMC reset . After 30 seconds , power on the Mac .
If your problem persist , you’re able to try reinstalling the M - series Mac ’s firmware . It ’s a procedure that ’s a fiddling more complicated than what you might be used to . You need another Mac with theApple Configurator 2app installed , a USB - C cable that bear out both great power and datum ( used to link the two Macs ) , and an internet connection . Apple has thefull details on how to revive or restore a Mac with Apple silicon with Apple Configurator 2 .
Apple pronounce you should n’t reset the SMC without first trying other troubleshooting tasks , such as force - quit problematic apps and restarting your Mac . However , Apple does n’t mention any negatively charged consequences of resetting the SMC , nor any fashion to find out for certain if the SMC is glitchy without readjust it and noticing that the trouble went away . We ’ve reset my Macs ’ SMCs many time with no apparent inauspicious effects , and on one function that did turn out to be the resolution to a trouble .
Before you may reset your SMC , you must shut down your Mac . After that , the process variegate depending on the case of Mac you have .
If this does n’t reset the SMC , shut down . On the laptop keyboard , press and prevail Control - choice - Shift ( your Mac might release on ) . Hold these key for 7 seconds , then campaign and hold the power button . If your Mac is on , it will change state off while you sustain down the Florida key for another 7 moment . Then let go the keys , await a few second and turn on the laptop .
Although neither of these procedures is a insure cure , both of them can solve a number of odd problems , and are worth a few second of your metre before hauling your Mac in to see the local Apple Genius .
There is no Terminal command for resetting the SMC .
