Secret Mac Boot Commands - Mac Boot Key Combinations

happy friday it's time for hands on mac this week we're going to show you all those little fiddly keys you can press at startup next hands on mac comes to you from twits lastpass studios you're focused on security but are you employees lastpass can ensure they are by making access and authentication seamless whether they're working in the office or remotely visit lastpass.com twit to learn more [Music] this episode of hands on mac is brought to you by roman get ed medication discreetly delivered to your front door go to getroman.com hom for a free online visit and free two-day [Music] shipping [Music] hey everybody leo laporte here time to delve deep into the macintosh computer and what i'm about to talk about probably is going to change i'm going to guess is going to change once the next version of mac hardware comes out the the silicon apple silicon based mac hardware but some of this stuff has been around since the very earliest macintosh computer back in 1984. maybe it'll hang on these are useful key commands for when you're first starting up and the most important is the one that people recommend all the time it's a little bit of a a voodoo two-step to fix mac problems and that's the reset parameter ram command there is an area of non-volatile storage storage it persists from boot to boot on your macintosh called nv ram and that nv ram uh contains things like what kind of hard drive what kind of screen all of the things that you know the bios cmos memory has on a pc that's stored in the same kind of place on a macintosh nvram in the old days whenever uh you had a problem with your computer one of the first things people said is reset the parameter ram and actually this command is easy to remember because it uses a p and an r key now this is a chord that means you're going to hit all four keys at the same time so shut down your mac turn it on and almost immediately you're going to hit the option key the command key that's the one with the funny little fan on it p and r option command p and r for parameter ram you're going to hold it down until you hear a sound now i don't know actually latest macs no longer make a bonging sound so i don't know if this is good what's going to happen on those but if you have a mac that bongs when it starts up when you command option pr you hold it during startup it will bong the screen will go black it'll in effect reset and you want to do this if you're doing the voodoo two-step and i have no idea whether this is required or not but generally the instructions will say do that a couple of times so you're going to let it keep holding it black maybe two or three times that's maybe once is probably enough then we're talking voodoo here but that will clear out the parameter ram that is something that sometimes actually does help you'll even see this on apple's support notes even on modern day macintosh's the other one is clearing the smc unfortunately there's no commit command key for that and clearing smc uh on which i think is a system memory controller on your system varies from laptops to desktops if if that is called for or you want to try it as a fix i remember on my trash can mac pro i had to clear the smc all the time to get usb working look it up because usually it's just unplug the machine and plug it in again you want to stop all power and restart but sometimes there's a key stroke sometimes there's other commands it's a very weird thing so those are the two things it's always good to know if you know if you mean an old timer you're talking about mac troubleshooting they'll always say have you cleared the parameter ram how about the smc that's how you do those but there are other commands actually some more modern commands that i think are also very useful let's talk about the mac os recovery system this is something relatively recent that i think is fantastic if you're ever having trouble with your mac if you can't boot it the hard drive you get the little question mark blinky or a sad mac try rebooting holding down the command and the r key sometimes on some max it's command option r sometimes it's shift option command r but usually command r is sufficient what's going to happen is it's going to boot into a special version of the operating system the recovery and it's going to pull up the recovery mode and you will then be able to in some cases actually not all macs but more recent macs download the operating system from the network so if you've got an empty hard drive you just took out the old drive put in the new drive nothing's on it or if you're having real trouble this is a very useful key command r once you get into the recovery system there'll be other options available to you if you have a firmware password you're going to have to enter that at this point and then you'll be able to restore from a time machine backup you can reinstall mac os you can use disk utility to format the drive there's a lot of commands in that recovery mode that's a very useful mode and i think perhaps one that i should emphasize if you do time machine backup this is an opportunity to restore your mac from that time machine backup so if for instance you get a brand new drive you want to get it back to the way it was you've been using time machine command r is your friend that gets you into the recovery system i mentioned firmware password i don't recommend doing this but if you really want your mac to be secure there are several levels i showed you a few episodes ago turning on file vault that i recommend it's an easy thing to do it's on in the new by default in the newer macintosh's older macintosh's you'll find it in the security system preference pane that scrambles all the data on your hard drive and makes it unusable but you can make your whole mac unusable by setting a firmware password on your macintosh i don't recommend it i've done it and it confu in fact i did it on a system i later gave my son and he said every time i boot up it wants a password what's going on and i said oh yeah that's i set the system firmware password i was experimenting with it but if you have a laptop and you're worried about it getting stolen you don't want the thief to use it at all let alone you know access your data on your hardware but you just don't want to use it at all you can set a firmware password which will keep the computer from starting up without that password uh turning it on is a little complicated you're going to go into that recovery mode we talked about command r and you'll see it in the utilities menu you can choose the firmware password utility turn it on there that's going to limit some of the following keys the keys i'm going to talk about on this episode not all of them work if you have a firmware password and whatever you do don't forget the firmware password it can really be a problem so in my opinion unless you know you need this for instance you lose your laptop a lot or you've got state secrets on there i think for most people the firmware password is a bad idea but i mention it because it is available to you and that is also in the command r section the recovery system there's also a startup manager if you're used to windows you know we have a safe mode a way to start up windows with minimal uh drivers running minimal software running there is a safe mode as well on the macintosh and it's the same key i think is in the windows which is to hold the shift key down during boot now that will be disabled if you have a firmware password that's one of the key strokes you can't use so turn off your mac turn it back on and immediately press and hold the shift key once you see the login window you can log in you may see a second one you should see safe boot in the upper right hand corner of your window and now you're in a mode much like safe mode on windows where you have a minimal set of stuff installed this is a great troubleshooting process because if things that were not working work in safe mode then you know it's caused by something that's loading later on in the startup process that'll help you narrow down what it is that's causing these problems so safe mode is a great feature that's something relatively recent on the macintosh there is a startup manager that i think is one of the best features of the macintosh and as far as i remember this has been around forever and that's holding down the option key on some mac keyboards it'll say alt on that key holding down the alt or option key during startup that lets you choose what you want to load if you're using for instance bootcamp you hold down the alt key the option key and you can choose whether to load windows or mac at boot time if you have bootable external drives or a bootable usb key that's how you choose to boot from it so the boot manager this is one of the great features of the macintosh it's very easily accessed on the mac just by holding down the option key on boot up if you have a firmware password turned on at that point you will be asked for the password before you can go on you see the value of that firmware password it really prevents people for instance bad guys from booting to an external disk and then exploring your internal disk uh so again it's for people who really want to keep their mac extra secure um there is also a diagnostics utility this is something relatively recent uh the diagnostic utility can be run in two ways if you press d on boot up it'll attempt to run the apple diagnostics that's already on your hard drive it's hidden in a special partition the way to do this a little weird and tricky you're going to disconnect everything all the external drives the only thing you want is keyboard mouse and monitor if you need ethernet you'll leave that in otherwise you can use the wi-fi and of course you don't unplug the power cord but any external hard drives anything else usb ports of any kind you want to disable all of those unplug them all shut down your mac turn it on and press and hold the d key apple diagnostics will launch and it will take a few minutes you'll see a progress bar and it's going to look for hardware issues this is something they sometimes run if you take your mac uh to the apple store it'll go through this checking for obvious issues it'll see if your wi-fi works you can actually repeat that after it's run once by clicking run the test again or pressing command r you can get more information pressing command g and once you're done running this test just click restart or press the r key to restart it or s key to shut it down this diagnostic mode is very handy now if you really have a serious problem with your mac you may find the diagnostic mode does not load locally if you instead of just hitting plain old d hit option d on boot it actually can load that from the network obviously you have to have a working network connection for this to work but it will load the apple diagnostics utility over the internet this is another command you can't use with a firmware password do you know what a netboot server is that's the ability to boot up over a network often used in big businesses or schools if your mac supports network booting n will start up from a netboot server or if you want to use the default boot image an option n instead that's kind of a specialty now there's a unique one that is i want to spend a little bit of time with actually i'll do a couple more and then i'll get i'll end up with this a single user mode because that's going to need uh additional explanation on older macs i think maybe even more modern max's certainly was a big thing in firewire max if you reboot holding the t key down t will put it in target disk mode that actually turns a mac into a hard drive it's a very handy way to copy data off a mac that's malfunctioning or to use an old mac to start up a new mac or vice versa holding down the t key and rebooting the machine worked really well on firewire because it became a firewire hard drive or more modern machines i think you can use ethernet to do this as well as a usb it'll work great with thunderbolt of course uh the most modern macs should work great that makes the basically this fancy computer your imac your mac mini uh your mac laptop into just the hard drive inside very handy for copying data over there is a verbose mode for people who like seeing a lot of stuff go up on the screen don't forget your macintosh really is a unix computer and anybody who's ever had a linux or unix box knows that the boot up process is all visible text scrolls up very fast on the screen and if you're quick you can read it and see what's going on that actually can be done on a mac i turn it on because i'm a geek i like to see it with a command line utility but you can do it ad hoc on a one time basis by pressing command v on reboot holding that down and then you'll get to do it once it's fun to see all the stuff starting up so there's a few of the commands now i'm going to talk about the last command which is single user mode and this is something that doesn't exist on modern macs they stopped doing it i think in mojave but it's a unix single user mode that's quite interesting and sometimes useful i've actually used it to fix a mac that won't boot or recover data so you're going to reboot the mac and you're going to press command s as it's booting up once you're in single user mode you actually can get a command line that will let you examine bits of the macintosh this is really a unixy kind of thing to do you can enter if you know unix commands you'll be at the command you'll be in a terminal in effect and you can use unix commands typically these commands are used to modify the boot process to modify the drive table or the boot manager it's not something to mess around with it's something you can't even do on more modern macs it's something that apple has kind of decided yeah better to leave this off it was a pretty hardcore command but if you've ever used single user mode on a unix machine or a linux machine apple actually did used to allow that all the way up to os 10 mojave and so if you have an older mac and you want to play with that command s on boot up and you'll start it up in single user mode you'll get a terminal and be careful because there's a lot of power there you are root user in that terminal and as a single user you can do things that in a multi-user machine you wouldn't be able to so believe it or not i mean there's a lot of stuff hidden under the surface this is all part of apple's boot roms uh and it's it's actually some of it very useful the the few that i think you'll use again and again command r i use all the time if i ever have trouble with a macintosh or with a drive i just want to get to disk utility and check the disk command r is very useful uh the shift key for for safe mode is great for diagnosing problems and don't forget if you want to do a little voodoo do a little chicken dance around your machine command option pr to reset p ram it'll impress the mac elders that's it for hands on mac a couple of useful things every mac user ought to know about even if you don't do it very often our show today brought to you by our friends at roman anyone who's dealt with erectile dysfunction knows how awkward it could be to talk about it in person roman connects you with a doctor licensed in your state you'll get discreet professional care genuine prescription medication or over-the-counter treatments delivered in unmarked packaging there's no commitment you can cancel at any time so if you're struggling with ed stay home and go to getroman.com h-o-m for a free online visit and free two-day shipping get roman.com h-o-m for a free online visit and free two-day shipping next week we're going to do something a little a little uh black diamond tip we're going to take a look at folder actions did you know you can trigger applescript or an automator script or a terminal script uh on simply copying something into a folder it's a very useful tool kind of arcane folder actions next week on hands-on mac i'm leo laporte i'll see you then bye-bye want more twit well you gotta check out ios today that's the show where leo laporte and i cover everything you need to know about ios it's the best apps the best games and everything you can do with your ipad your iphone and your apple watch plus car kit and so much more twit dot tv slash ios [Music] you

Channel: Hands-On Mac

Views: 475,329

Keywords: Leo Laporte, Hands On Mac, Mac, Apple, Macbook, Mac Pro, iMac, Mac help, Mac how-to, Macbook help, macbook how-to, iMac help, iMac How-to, Mac Pro help, Mac Pro how-to, zap the pram, zap the p ram, Reset Parameter RAM, Option Command P R, Clear SMC, Boot to Recovery Mode, firmware password, recovery mode, Utilities Menu, Safe Mode, Startup Manager, Diagnostics Utility, Target Disk Mode, Verbose mode, Single user mode, mac boot commands, mac recovery mode, mac safe mode

Id: VwNYWAxHCgM

Length: 18min 24sec (1104 seconds)

Published: Fri Aug 07 2020