El Capitan Installer App

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The El Capitan installer is downloaded to the /Applications folder, with the file name 'Install OS X El Capitan.' If you've installed El Capitan and want to create a bootable installer, re-download the installer from Apple. Aug 15, 2016 Mac OS X El Capitan 10.11.6 Intel USB Install Download. Click on below button to start Mac OS X El Capitan 10.11.6 Intel USB Install Free Download. This is complete offline installer and standalone setup for Mac OS X El Capitan 10.11.6 Intel USB Install.

The new OS X El Capitan features a new Split View, features in Safari, Mail, Notes, Maps, and Photos, and more. To get your hands on all this new stuff, you have to install the operating system on your Mac.

Download El Capitan Without App Store

If you want to perform a typical OS upgrade, it’s easy. You download it through the App Store. Here, we’ll go through the steps of installing EL Capitan from Yosemite.

It’s about preparation

Before you install the upgrade, there’s a little bit of prep work you should do. Our article on how to get your Mac ready for OS X 10.11 El Capitan is what you should read before you proceed. It covers:

  • Compatible hardware and older versions of OS X
  • Verifying the health of your Mac
  • Installing updates
  • Backups
  • Encryption issues

Go read that article and come back here when you’re ready to go.

How to download El Capitan

Apple provides the El Capitan upgrade through its App Store. The download is a bit over 6GB, so you may want to download it at a time when you have other things to do—how long the download takes depends on your Internet connection and the amount of activity at the App Store. Or you can use your Mac while you wait, but be ready to save your work and quit when the download is done.

To download El Capitan, launch the App Store app in your Applications folder (or go to Apple menu > App Store). You’ll probably find El Capitan right away, especially if go to the App Store soon after the official release. Apple will probably have a banner at the top promoting El Capitan, but if you don’t see one, you can probably find it in the Free section in the far right column (you might have to scroll down to see it). And you can always do a search on El Capitan.

When you get to the El Capitan page in the App Store, click on the Download button. You may have to enter your Apple ID name and password, and after you do, the installer will download.

Copy the installer

When the download finishes, the installer automatically launches. Don’t click Continue in the installer just yet. What you may not know is that the installer is downloaded to your Applications folder and then deleted after the installation is done.

If you ever need the installer again, you can get it in the App Store. But I like to make a copy of the installer. I often have to perform OS installations, so I make a bootable flash drive that I can use; it’s a lot faster than waiting for the download.

To copy the installer, you need to hold down the Option key as you drag the Install OS X El Capitan app in your Applications folder to the copy destination. If you don’t hold down Option, you’ll create an alias, not a copy.

Install El Capitan

OK, now you can click that Continue button in the installer window. (If the installer isn’t running, go to your Applications folder and double click the Install OS X El Capitan app.) You’ll be asked to agree and then confirm that you agree to the license agreement.

The next screen will ask you to select the disk for the El Capitan installation. If you have one storage device with one partition, you’ll see it in the installer window. But if you have multiple storage devices and/or multiple partitions, you can select the one you want by clicking the Show All Disks button. Make your selection and click Install.

To continue, you must enter your username and password. The install will prepare to install, restart your Mac, and perform the installation. The Mac may restart again during the installation process. The install will take several minutes, so you may want to go for a walk, call your mom, take a nap, or catch up on chores while the software does its thing.

When the installation is finished, the Mac will restart and you’ll need to log in with your username and password. You may be asked if you want to send diagnostic data to Apple and that you need to log in with your Apple ID, and then a setting up screen will appear and go away. You’re done.

Want to do a clean install of El Capitan?

A clean installation is when you install the operating system on a blank storage device. You can do this by creating a bootable El Capitan installer, and then use it as the boot drive for your Mac. You run Disk Utility to erase your drive and then proceed with the El Capitan installation.

Once the installation is done, you use Migration Assistant to transfer your data from a Time Machine backup.

Why should you do a clean install? Maybe you partitioned your storage device and want to change the scheme. Or maybe you’ve installed and removed lots of apps over time and want to get right of any lingering software components—if this is the case, don’t restore your data from a Time Machine backup. Manually copy your files and reinstall your software.

Recently, I reinstalled macOS on my device. Throughout the process, manyattempts failed miserably. But I now have some experience and assorted hints onwhat to try.

Mac

DISCLAIMER: All information in this post is provided as-is, and some of it mayvoid your warranty. Neither Chris Warrick nor Apple will be responsible for anydamage to your devices caused as a result of using information in this post.

Contents

The best, safest, least error-prone way to do an install is with a USB stick.Unfortunately, making a USB stick with the macOS installer on it is a nuisance.The expected way to produce macOS install media is to download the installerfrom App Store/Software Update, and run the createinstallmedia command-lineprogram included with that installer app. All is well, as long as macOS works.If it doesn’t, and Recovery can’t install it for you, that can be difficult tosolve.

Apple does not make macOS images publicly available. That’s probably to makeHackintoshing this little bit harder, but this also affects legitimate users.The only thing you can download from Apple is El Capitan. Apple offersInstallMacOSX.dmg on theirwebsite. If you take a look at the instructions, you will see that this isnot a bootable OS X image. This image has a .pkg package. This package isexpected to install /Applications/Install OS X El Capitan.app. Well, we’rein recovery, we can’t install stuff. So, let’s do this the manual way.

Turns out the .pkg format is just an archives all the way down, with allarchives being different formats (at least three).

The first archive is the .pkg file itself. Those files are in XAR format, which was invented by theOpenDarwin community. You can either extract it with pkgutil --expandfoo.pkg foo_files (the last argument is the destination directory, can beanything, will be created by pkgutil) if you have access to that command (it’savailable in Recovery OS), or you can try the xar utility as xar -xffoo.pkg. The structure produced by both tools is a bit different, but we canwork with both.

The second archive-in-archive is the Payload. It’s a gzipped cpio archivethat contains the files installed by this package. If you have BSD tar(default on macOS, easily installable on Linux), you can just do tar -xvf Payload.Otherwise, you can use gunzip -c Payload | cpio -i (or gzcat). Thatwill extract all the files the package has.

Another nested archive is the Scripts archive, although note thatpkgutil will extract it automatically. If it’s not extracted, it’s actually.cpio.gz again, with the same way to extract it.

(PS. If you have 7z around (on Windows/Linux as well), you can just pointit at all the compressed files mentioned in this paragraph.)

Let’s expand the El Capitan package.

We’ve got the installer app, which is what we need to create an install image.Great, let’s try it!

Apple Download El Capitan Installer

Oh, we’ve got a problem. Turns out there’s one more thing we need to take careof, and it’s the scripts. MacOS packages have scripts, typically shell scripts,that are run at various stages in the install process. We can look at thePackageInfo file, or just look in the Scripts folder, to see thatthere’s an link_package script we need to run. This script creates aContents/SharedSupport directory inside the installer app, andcopies/hardlinks the InstallESD.dmg file (which is the install formerly-DVDimage) to that directory. Let’s try doing this on our own:

And it works! createinstallmedia will now produce valid install media.

If you are in Recovery, you can find an Install app on the filesystem. If youtry to run it, you will get the same error as in the previous paragraph:

This also happens with some older macOS versions, where you get a small.app from the App Store, and that app does the actual download.

Whatever the issue was, we need to download the install files with theinstaller. Open the installer and let it run until the download finishes. Ifthe app asks you to reboot, quit it at this point. If it never asks, you canstill find a way to get files out (after a failed install, they should not beremoved).

Os X El Capitan Installer Application

The install files can be found in /macOS Install Data on the destinationvolume. For older versions, you will just have InstallESD.dmg, newerversions add more and more files, some of which are hardware-specific (andCatalina has InstallESDDmg.pkg, because Apple loves nesting archives for noreason!). However many files you find, you can just:

  1. Copy Install macOS Catalina.app to a read-write volume.

  2. Copy the contents of /Volumes/TARGET/macOS Install Data to InstallmacOS Catalina.app/Content/SharedSupport. Make sure you account for hiddenfiles, if any (copy the entire directory). If you did this correctly,InstallESDDmg.pkg (or InstallESD.dmg on older verisons) is in the SharedSupportdirectory (not in a subdirectory).

  3. Run createinstallmedia. It should now consider the installer valid. Theavailable options differ slightly depending on the OS version.

If you get this error, it might be because Apple’s signing keys expired, orbecause of other date/time weirdness. Regardless, you can force an install ifyou are sure the installer is not damaged with this command (source):

While messing with all the installer stuff, I found out a fewinteresting/worrying things about the download process.

The first one is that the macOS installer uses plain HTTP without encryption todownload files. That opens you to all the standard issues — an attacker canreplace files you download, and the protocol doesn’t do anything to detecterrors (the installer will verify files, but where do the checksums comefrom?).

The second one is how the download happens. You might have noticed it to be abit slower than usual traffic. The download happens in 10 MB chunks, using theRange HTTP header. The installer asks for 10 MB, gets it, saves, asks foranother chunk. Repeat that over 800 times, and the overhead of the entire HTTPdance becomes noticeable. (I haven’t checked, but I hope the installer at leastuses Keep-Alive. I wouldn’t be particularly surprised if it didn’t, though.)

But this raises another question. The servers clearly support partial downloads.And yet, if your network disconnects during the download, your downloadprogress for that file is reset, and in Catalina, you can go from 8 GB back to500 MB if you’re particularly unlucky. The question is, why? Thisinfrastructure should make it trivial to continue the download, perhapsdiscarding the most recent chunk if you’re concerned about that download of itbeing unsuccessful.

The first time you boot a Mac after a clean install, it starts the SetupAssistant. This app asks for basic OS settings (locale, date/time, useraccounts), and also lets you restore user data from backups.

Sometimes, you might want to access the Terminal or Console from that screen.You can do that with Ctrl + Opt + Cmd + T and Ctrl + Opt + Cmd + C respectively (source).

How could that come in handy? For example, if you want to check if the backupdrive still worked and if the process isn’t stuck (I wrote a test file and alsochecked top).

A few months later, in December, I upgraded to Big Sur and then installed Windows 10alongside it in Boot Camp. I then did some more hacks, which led totwo unbootable OSes.

As part of the upgrade, I had prepared install media and used it to install (soit wouldn’t fail, as it did last time), and made a .dmg of it with DiskUtility. (Also, Apple won’t tell you this, but you need to give Disk UtilityFull Disk Access for disk imaging to work. Otherwise, you get a crypticerror.) I erased the USB drive after installing, but hey, I could get it back.I booted into Internet Recovery and restored my image. Big Sur failed to bootand showed a 🚫 sign. I triedrestoring my Catalina image from the previous reinstall, and that didn’t workdue to a size mismatch. I used a different USB drive than these months ago (Ididn’t have that one with me at the moment), and apparently the one I used hada different size (both are marketed as 16 GB). The images could be mountedfine, and createinstallmedia should have worked, likely producing abootable drive.

Time Machine is Apple’s magical backup solution. Time Machine saves snapshotsof your entire disk. It’s supposed to help restore files that were deleted orchanged in an unwanted way, or help you restore a full macOS install.

Time Machine is great at file recovery, but none of my 3 system restoreattempts were successful. Attempt #1 was a full Time Machine System Restore,from Recovery, back in June. It failed partway through, it couldn’t readeverything from the disk. There might have been underlying hardware issues withthat failure, so I had another attempt.

Attempt #2 was a Migration Assistant restore, as part of the initial setup.This one succeeded, and things worked… except for one fairly important app.This app requires online activation with the vendor, and it wouldn’t reactivateafter the install. Whatever the third-party vendor is doing didn’t like thereinstall. I tried to nuke all the things in ~/Library related to theirsoftware, and ran their nuke-everything uninstaller, but that didn’t work.I reinstalled from scratch and copied over my files, settings and apps from theTime Machine drive.

Attempt #3 involved the System Restore again, this time for the Decemberreinstall. The hardware issues were all fixed in the meantime, so I went for aTime Machine System Restore.

Issue #1: Internet Recovery booted into Catalina. There was an issue on Apple’sside, Big Sur was unavailable in Internet Recovery in December. TMRecovery will not restore a backup created with a newer version of macOS thanyou’re booted into, so I was forced to restore a slightly older Catalinabackup. (I spent most of my time in Windows during that weekend, so other thanthe need to upgrade macOS to Big Sur again, I didn’t really lose any data dueto this.)

Issue #2: It wasted time computing an inaccurate size estimate. Beforerestoring a backup, macOS first checks if it will fit on your drive. When itdoes that, an indeterminate progress bar is shown. macOS won’t tell you theresult of that computation, but you can read the final value from the fullInstaller Log (Cmd + L). On my Mac, the value was 96.2 GB. I was at the Macwhen it was getting close to that value. 94, 95, 96, 96.1, 96.2, 96.3… hold ona second, 96.3 GB? Hopefully that’s just a bunch of extra things that areinstalled from the system image directly, or something like that, right? Ofcourse, since the progress bar is based on the pre-computed size, it becameindeterminate and I couldn’t tell when it would end. 98, 100, 110, 120, 121.2GB is where it ultimately ended. So, not only did it waste 20+ minutescomputing a size, it was off by 25 GB.

Issue #3: The restore didn’t work. The System Restore finished and claimed tohave succeeded, but macOS wouldn’t boot. It showed an Unrecoverable error,SecurityAgent was unable to create requested mechanism. Most people who had asimilar error had it caused by a botched TeamViewer uninstall; I didn’t havethat installed, and it was referring to a different component. So, wipe andfresh reinstall it is.

I copied my stuff from the TM drive, and it was acting weird. Some apps failedto load their settings copied into Library, others started with a “Move to/Applications?” prompt (even though they were in that directory). For somereason, those files had some hidden attribute set on it. I worked around it byputting files in a .zip archive with Keka, and then unzipping them;xattr might also help. (The attribute was likely com.apple.quarantine.)

After I got the Mac to work, I reinstalled Windows and set up rEFInd, and itnow works fine. (I only use rEFInd because I want virtualization in Windows,and that doesn’t work unless you’re warm-rebooting from macOS. I don’t needanything more advanced than the Option key boot menu, but Apple made me use athird-party bootloader.)

We now go back to the original post from June.

Dear Progress Bar Designers: can you please make your progress barsfunctional? The macOS progress bar might look sleek at just 7 px (non-Retina)/6pt = 12 px (Retina) high, but at the same time, you’re looking at individualpixels if you need to know if it works or if it’s stuck. I have had to point mymouse cursor at the end of the filled-in part just to know if it’s working ornot. Or sometimes, put a piece of paper in front of my screen, because there isno mouse cursor when macOS installs on the black screen. How to makethat progress bar easier to use and more informative? Just add numbers on top ofit. For long-running processes, I wouldn’t mind progress bars that said“12.34%”. That specific Setup/Migration Assistant window should be changed (itonly has a remaining time estimate and transfer speed, it should also showmoved data/total size), but wouldn’t more things benefit from a clearindication of the progress? Yes, perhaps it looks less sleek, perhaps itrequires more space for the bar.

Just compare: which is easier to parse? Which is more informative?

64.64% (6.7 GB/10 GB copied)

I’d honestly be happy enough with option 2, at least it can be read easily andyou can remember the number instead of a vague position.

After all this, I managed to get macOS Catalina installed. After variousfailures in built-in El Capitan recovery and Catalina Internet Recovery, I firstinstalled El Capitan with this hack, then jumped to Mojave because I thoughtthe new Software Update would help (it didn’t, same installer, samefailed-to-extract-package issue), then made a Catalina USB stick, and itfinally clean-installed, but I was worried about the backup disk’s operation,and I used a proxy on my local network to try and speed up Catalina downloadswithout much improvement… but hey, at least it works. Apple should really makeit easier to install their OS and to make boot media even when stuff doesn’twork, even from Windows. The Hackintosh folks can just find someone with aworking Mac and ask them to download from App Store and make install media, orfind less legitimate sources, they probably don’t care as much. But if my ownsystem crashes, I’d probably want to get working install media immediately,myself, and from Apple. Without all this mess.