![]() ![]() If your problems persist, you can try reinstalling the M1 Mac’s firmware. Disconnect all USB devices (except your keyboard, if it’s a wired keyboard), hold the power button down until the Mac shuts off completely, and then press it again and immediately hold down Command-Option-P-R. The most likely cause is that your Mac isn’t registering the key presses due to wonkiness with a USB device. If you hold down Command-Option-P-R at startup and you see nothing but a gray screen that doesn’t change for several minutes-no Apple logo, no progress bar, no second startup chime-don’t panic. Then check the Startup Disk, Display, and Date & Time panes of System Preferences to make sure they’re set the way you want them.If you have an older Mac that chimes at boot, hold down the keys until you hear a second startup chime. Then let go and allow your Mac to continue starting normally. Keep holding down those keys for about 20 seconds.Press the power button, and as soon as you power up the laptop, hold down Command-Option-P-R. ![]() To reset your NVRAM, you use exactly the same procedure you once used to reset PRAM. NVRAM serves approximately the same purpose as PRAM, but instead of storing a dozen or more pieces of information, it now contains just a few: your selected startup disk, speaker volume, screen resolution, time zone, and-if your Mac has crashed recently-details of the last kernel panic. Modern Macs no longer use PRAM they instead use something called NVRAM (NV for non-volatile). So you could press a key sequence at startup to reset (or “zap”) the PRAM, returning it to default, factory values. If the values in this memory got out of whack for one reason or another, your Mac might not start up correctly or might exhibit any of numerous odd behaviors afterward. The P in PRAM stood for “parameter” (the RAM was just RAM-random access memory), and it referred to a small amount of special, battery-backed memory in every Mac that stored information the computer needed before it loaded the operating system. ![]() Back in the day, the standard list of quick fixes for random Mac ailments always included clearing the PRAM. ![]()
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