Resetting PRAM through Terminal
For some reason, my Mac won't let me reset my PRAM in the usual way (by holding the relevant keys down when restarting), simply nothing happens when I try it and my Mac just boots up normally every time.
I'm suspecting this may be due to the fact I'm using a PC keyboard after I broke my Apple one a while back.
I read that I can reset my PRAM through Terminal with the following command:
sudo nvram boot-args=”-p -r”
But all I get is this error:
nvram: Error setting variable - 'boot-args': (iokit/common) general error
I'm running High Sierra on a late 2009 iMac if that helps
Solution 1:
According to an Apple Support page called "Prepare your institution for iOS 10 and macOS Sierra":
...you must use the nvram command to properly set boot-args NVRAM variable. Starting with macOS Sierra, you must be booted to the recovery partition to run this command.
But now you can clear the NVRAM with
sudo nvram -c
Then restart for the reset to take effect.
I also have a PC keyboard that doesn't seem able to reset the NVRAM on startup, but I think the real problem is that it's wireless. But this command is easier and more reliable anyway.
Solution 2:
Sounds like a SIP restriction rather than a keyboard issue. Read through the linked article to get an idea of what SIP is, and then try this:
- Ensure you have an up-to-date backup, in case of emergency.
- Power off your Map as normal.
- Hold down Cmd-R and press the Power button. Windows keyboard should be Win-R instead. Keep holding the keys down until the Apple logo appears, then release.
- Wait for macOS to boot into the recovery utilities window.
- From the Utilities menu, choose Terminal. Then:
csrutil disable, thenexit, then reboot into High Sierra as normal.
I'm not sure where you're getting -p -r as boot args to reset NVRAM, but sudo nvram -c should do the trick on High Sierra, as Tetsujin states here.
When you're done, reboot into recovery mode once more, open Terminal and then re-enable SIP with csrutil enable, and reboot into High Sierra.