Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [nvram]

Non-volatile random access memory; RAM that doesn't lose the stored information when the power is turned off, unlike traditional RAM

11
votes
4answers
38k views

Trying to set boot-args with nvram gets “general error” on Sierra

I'm trying to temporarily disable KEX signing enforcement on my MBP since my company's VPN client (GlobalProtect) is failing the signature check now. This started yesterday when I did the OS upgrade ...
9
votes
4answers
27k views

El Capitan /private/var/folders cache files consuming 30–40 GB

I've upgraded my MacBook Pro to El Capitan recently, and one of the first unpleasant changes, other than XtraFinder & TotalTerminal no longer being compatible, is that the system deems it ...
8
votes
1answer
13k views

How can I view/inspect my Mac’s Parameter RAM (NVRAM)?

Inspired by this question I started looking for apps that allow to read the data saved in my Mac’s Parameter RAM. Aside from a very antique (pre OS X) application for Classic, I could not find any. Is ...
8
votes
1answer
5k views

iMac restarts instead of shutting down

I have a problem with my iMac restarting when it should be shutting down. This doesn't happen all the time but appears to happen more frequently when I've had the computer on for a few hours. What ...
6
votes
2answers
4k views

MacBook Pro now asking to login with password, but can't do this via built-in keyboard

I have read a number of threads including this one How can I reset the PRAM if Recovery Mode keeps overriding the PRAM command? Where Adriano says "PRAM reset is not working because you turn on ...
5
votes
1answer
12k views

What does “sudo nvram boot-args=”debug=0x10“” do to my Mac?

Because Parallels Desktop 10 and Fusion 7 both run slow on Yosemite, there are KB articles which make the users execute sudo nvram boot-args="debug=0x10" For instance here: http://kb.parallels.com/...
4
votes
6answers
24k views

Desktop icons have disappeared after using HDMI cable (Yosemite)

I had a strange issue recently where I had to reset PRAM after using an HDMI cable with my MBP (it had a blank screen on boot). I feel like this is again related to the HDMI cable. After using it, ...
4
votes
0answers
306 views

Does system integrity protection prevent nvram(8) from setting -x as a boot argument for safe mode?

When pre-release macOS Sierra is in safe mode with -x as a boot argument in NVRAM, the following command works as expected: sudo nvram boot-args="-v" When Sierra is booted in normal mode, the ...
3
votes
1answer
49k views

Resetting PRAM without a(n) (Apple) keyboard?

A while back I had an issue with my (2013) iMac not recognizing the keyboard after it was unplugged and re-plugged in. I had to actually power down the iMac and power it back up before it would ...
3
votes
1answer
5k views

nvram boot-args to boot in target disk mode

I'd like a Mac to always boot in target disk mode. Similarly to setting sudo nvram boot-args="-v" which boots in verbose mode, I tried sudo nvram boot-args="-t" but to no avail. Any idea?
3
votes
3answers
8k views

How can I reset the PRAM if Recovery Mode keeps overriding the PRAM command?

Lion uses the ⌘ + R to boot into recovery mode. Resetting the PRAM in anything less than 10.7 was ⌘ + ⌥ + P + R. Recovery mode now seems to override the PRAM command. Does anyone ...
3
votes
3answers
6k views

Clearing NVRAM on Yosemite shows password entry

When I make the ⌘ Cmd+⌥ Opt+P+R it shows a dialog with lock symbol and to proceed I have to give the password but this way I'm not able to proceed with the resetting of the PRAM. How can I reset the ...
3
votes
2answers
5k views

Setting a NVRAM variable in normal boot not permitted but allowed in recovery mode

If memory serves me right then in Yosemite it was possible to set the NVRAM variable agc with nvram boot-args even in normal full boot mode. This seems to have changed in later versions of the OS. ...
3
votes
1answer
1k views

Macbook Pro: CAPS always on, Backspace key not working: Faulty Keyboard?

Do I have a faulty keyboard or a Firmware / OS problem? Apologies for long post, but I want to clarify all I have attempted and to point out some doubts. Macbook Pro Mid 2010 Intel OSX 10.11.4 I ...
3
votes
1answer
1k views

Spoofing a serial number on a MacBook Pro

I have a MacBook Pro that got liquid spilled on it. I cleaned it up and everything works except the fact that it no longer has a serial number. When I go to look at System Information, it says "Serial ...
3
votes
1answer
11k views

Can Find My Mac still persist after erasing the hard drive?

I have recently acquired a MacBook Air 2011 off of ebay. In order to avoid second-hand Mac issues relating to iCloud remote shut downs, I have performed the following actions: Secure erase (using ...
3
votes
2answers
1k views

On lid open Macbook Pro 2016 boots automatically - after turning off I need to juggle 10 seconds with the touch id power button to boot

I have the late 2015 (15 inch) MacBook Pro. By default it turns on when laptop lid is open. This is not good for me, sometimes I open the lid on weak battery to make sure it's not turned on, so I ...
3
votes
1answer
2k views

No boot-args in nvram

After seeing this question regarding the serverperfmode nvram boot-arg, I thought I would check my server to see its status: $ nvram boot-args nvram: Error getting variable - 'boot-args': (iokit/...
3
votes
1answer
409 views

MacBook Pro will not wake from sleep after installing third party application

I installed an application called Air Parrot that uses air play with an Apple tv to mirror or extend the desktop. I noticed that after I installed it, I am no longer able to wake my Mac from sleep. ...
2
votes
2answers
3k views

Can't reset PRAM and reinstall OS!

I have a problem with my MacBook Pro 2010 13 inch, 2.4 GHz. Originally I had Snow Leopard installed on my Mac, then I was trying to upgrade it to Lion (official version from App Store). During the ...
2
votes
1answer
59 views

Find My Stolen Mini Mac After Installing New Clean Mac OS X Installation

My Mac Mini was stolen from my office and I think it was stolen by my colleague. They are all software engineers and I think the thief will install a fresh version of macOS on the stolen Mac Mini. My ...
2
votes
1answer
36 views

Is there an equivalent of Linux's kernel memmap on OS X?

According to memtest86, there is a persistent single bit error in my MacBook Pro's 16GB of DDR RAM. Since the error is in the second half of the physical address space, I can work around the problem ...
2
votes
1answer
169 views

MacBook Pro 2012 15" can’t boot

When I turn it on, it shows the Apple logo and starts loading up to about 50%, then the screen turns black. Running the hardware test shows this: Alert! Apple Hardware test has detected an error. ...
2
votes
1answer
251 views

MacBook Pro Mid 2012 startup chime from right speaker only

After installing a ssd into my Macbook pro mid 2012 (not retina), i noticed that the startup chime is coming only from the right speaker. (I am not sure if it was always like that or if its because of ...
2
votes
1answer
94 views

System boot chime right speaker only

I recently replaced the internal hdd inside my macbook pro mid 2012 with a ssd. Now it seems that the system chime (the "boong" that goes off when i turn it on) only plays through the right speaker. ...
2
votes
1answer
234 views

Yosemite turns on “reduce transparency” at every login or wake after battery failure

Recently, I was using my rMBP on battery power, with about 20%-30% remaining battery, according to the battery indicator. It suddenly shut off, and would not power on (not even showing the "battery ...
1
vote
1answer
860 views

How to see everything in the NVRAM

I know you can show the contents of the NVRAM with sudo nvram -x -p, but doing that doesn't seem to list everything. I say this because I just had an issue with the resolution of my screen at boot, ...
1
vote
1answer
47 views

Does NVRAM, PRAM or SMC have anything to do with the red light on a Riser lighting up but then not lighting up after a reseat and riser switch?

One of the red leds for dimm 3 raiser b lit up red on my MacPro early 2008 lit up, so I reseated the ram in question on it by switching it with it's counter part (swapped dimm 3 for dimm 4) and ...
1
vote
1answer
2k views

PRAM and NVRAM differences and overlap with eachother and UEFI firmware chip

Is PRAM stored on the same NVRAM chip that non-PRAM variables are stored. I always assumed that NVRAM was the UEFI firmware chip on the logic board. Are all of these one in the same (NVRAM - PRAM - ...
1
vote
1answer
20 views

MacBook Pro keep on “unplugging” battery and need SMC/PRAM reset

I recently brought my 2015 13" MacBook Pro to an Apple center to get a screen replacement for Staingate. They did it for free. Before this replacement my MacBook was doing really good actually. After ...
1
vote
1answer
39 views

How to find out whether NVRAM was reset?

I was having some issues with my mac so I reset NVRAM by holding ⌘+⌥+P+R. The problem is that this laptop does not chime when NVRAM is reset, so I'm not sure if NVRAM was indeed reset. How can I ...
1
vote
1answer
40 views

Disable Macbook internal display

I own a Macbook Pro 13 2017 (2 thunderbolt ports), and I would like to disable the internal display when an external monitor is connected to it through USB-C. I have ruled out the following Turn ...
1
vote
1answer
257 views

Does resetting NVRAM reset EFI Boot Order?

I've had a Macbook Pro for a year or so now and have experimented with quite a few Linux distributions which have added and changed things in the EFI Boot Order. I am looking to clean things up. The ...
1
vote
1answer
54 views

Preferred Order of NVRAM/PRAM, SMC, and OS resets

Is there a preferred order in which I should reset the NVRAM/PRAM, SMC, and OS on my MBP? If so, what is this order (and why)? Edit: I intend to do all of them to completely reset my computer. No ...
1
vote
1answer
384 views

White Screen – nothing works after NVRAM reset

I can't boot my iMac (27", late 2012) and only get to see the white screen. Nothing works, CMD+R, CMD+ALT+Shift+R, Shift, C, CMD+S, ALT … I can hear the startup chime, screen goes white and stays ...
1
vote
1answer
992 views

MacBook Pro won´t let me log in after PRAM

I was having a problem with a pointer so after installing latest system updates with no effect on crazy pointer, I did a PRAM reset. From then on, a log in page has changed: my user name has ...
1
vote
1answer
531 views

Command Option P R not working with Bootcamp installed [closed]

I have an error 43 when trying to delete a folder in Mac OS - I have read that to fix this I need to reset the NVRAM - to do that I need to boot with Command OptionP R - however, this makes the ...
1
vote
1answer
208 views

MacBook Pro (late 2013) w/ Yosemite & FileVault won't boot: LCD light only, no other activity

After lid-sleeping my machine with ~10% battery left, a few hours later, attached to AC power, it would not wake from lid-open, keypress, or short power-button-press. After doing a long-power-button-...
1
vote
2answers
3k views

Troubles with resetting PRAM

I followed Apple's instruction to reset PRAM ("Press and hold the Command-Option-P-R keys before the gray screen appears.") and the only thing that happened was that my Mac rebooted repeatedly until I ...
1
vote
0answers
36 views

How is modifier key remapping implemented on Touchbar Macbooks?

How is modifier key remapping implemented on Touchbar Macbooks? Is it done by the main OS, or is it delegated to a controller associated with the keyboard itself? I understand that the Touch Bar and ...
1
vote
0answers
34 views

What is stored in the NVRAM that could cause my Macbook Pro to fail to detect sound output devices?

My Macbook Pro (2016, 4 thunderbolt 3 ports) has this very annoying problem where something breaks in the audio system, and it stops playing sounds and being able to detect any output devices. It's ...
1
vote
0answers
181 views

Macbook turns off before battery is 0% when left unplugged. (Already reset SMC and PRAM several times) [duplicate]

This is my first question on this forum. My MacBook has been turning off randomly when left unplugged. It shuts down before the battery indicator reaches 0%. I have reset the SMC and PRAM several ...
1
vote
0answers
603 views

MacBook Pro stuck on gray boot screen

This morning, my mom logged into her computer as normal, used Mail to check her email, and then got distressed when seeing "squiggles and lines" on her monitor. When trying to restart her machine, it ...
1
vote
1answer
378 views

Reset PRAM in MacMini 3,1 (Early 2009) and now it won't boot at all, but powers on and chimes

I was having problems booting to Apple Hardware Test and decided to reset the PRAM. Big mistake; now it won't boot at all. It's a Mac Mini 3,1 (Early 2009) running El Capitan. PRAM reset chimed twice. ...
1
vote
0answers
259 views

saving / restoring the NVRAM

I need to find a reliable way to save and restore the contents of NVRAM. Would this be correct? Preservation nvram -x -p > ~/nvram.xml Recovery: sudo nvram -x -f ~/nvram.xml
1
vote
1answer
274 views

Do I need NVRAM/SMC reset to restore a used MacBook Air to defaults?

I've bought a used MacBook Air (Mid 2013) running Yosemite and I'd like to restore every setting to defaults, as in, start over with a fresh clean OS. What are the things I have to run to make sure ...
0
votes
1answer
238 views

How to reset NVRAM on iMac with bluetooth keyboard?

I have a problem with a swipe back in Safari. On my MacBook I could fix it by resetting of NVRAM. I can't find out how to do it on iMac with a Bluetooth keyboard. Do I really need a cable keyboard in ...
0
votes
3answers
13k views

Poor battery performance after SSD install

I recently installed a Crucial SSD into my Macbook Pro (2.66 GHz Intel Core i7), and now the performance of my battery is probably about 50% of what it used to be. I've tried to reset the PRAM, but ...
0
votes
1answer
156 views

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 ...
0
votes
2answers
78 views

How to enter various nvram boot-args

I'd like to set both vm_compression=1 plus serverperfmode=1. Can I achieve this by nvram boot-args"vm_compression=1","serverperfmode=1" Regards, Stefan