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Macbook Pro 13" 2015 with OS X Yosemite on board. I've been trying to install OS X El Capitan, but always get the following message: "This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading."

By the way this is not a date time issue, date is correct on my computer.

enter image description here

How can I fix this? Who knows the solution, please help.

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Have you deleted the "Install OS X El Capitan" application bundle and downloaded it again? – user3439894 Nov 22 '15 at 17:21
    
& where did it come from? – Tetsujin Nov 22 '15 at 17:25
    
@user3439894 I'm actually trying to download it again. Internet connection is poor, so I'm waiting. And yeah, there is no previous copy of the installer app in /Applications/ directory. – presscorp Nov 22 '15 at 17:26
2  
If you're already doing as the message suggested and haven't finished the new download and tried installing again, then why did you even post to begin with? If you're having trouble with maintaining a constant connection or have a connection fast enough to get it downloaded in a timely manner you may need to find a better connection for the download. – user3439894 Nov 22 '15 at 18:12
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Try using a USB installer? – Angelplayer Mar 22 at 21:40

Follow this tutorial. This applies to the reply from @Cazuma Nii Cavalcanti. In short once you are at the first install page go to tools in the nav bar and open the terminal, in the terminal type date MMDDHHmmYY replacing the letters as follows.

MM - 2 digit month  01 - 12
DD - 2 digit date   01 - 31
HH - 2 digit hour   01 - 24
mm - 2 digit minute 01 - 59
YY - 2 digit year   > 15

once that is done go through the install normally. I just tried it and it worked with a USB install of OS X (10.11 - El Capitan) and it worked like a charm!

If setting to correct date doesn't work. Set to a date just after the os release.

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This should be the accepted answer. – Chris Beck Feb 2 at 4:22
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The installer date made a big difference for me. When I set the date of the machine close to the date of the installer, installation proceeded with no difficulties. – user171792 Feb 18 at 6:16
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Setting a date near to the date your downloaded the installer , is a solution for fix the message and OS X El Capitan install begin normally and finish ok. – user172064 Feb 20 at 0:42
6  
I just met the same problem. After set the date to today (2016-02-29) it still failed. Then I set to an earlier date (2016-01-01) and it worked. Weird. – aleung Feb 29 at 15:56
1  
Set the date earlier from the current date e.g., if today it's the 29 Feb 2016 set it as the 1st Feb 2016. This worked for me. – user173477 Feb 29 at 18:43

I ran into this problem. I had installed a brand new SSD; I downloaded the installer and created a bootable USB stick. Everything looked raring to go. Hours later...

The ways to resolve this process:

  1. Try setting the date to today's date as documented EVERYWHERE. If the install still fails:

  2. Use htiutil to verify the checksum. Assuming you have the El Capitan download in the Applications folder, you can verify the download with the following command:

    hdiutil verify /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/SharedSupport/InstallESD.dmg
    
  3. When did you download the installer? Apparently my problem was that I had downloaded the installer a number of days ago and the certificates had expired. If setting to today's date does not work; and the htiutil command came back with "is VALID"; try setting the date to the date your downloaded the installer.... or possible a few days earlier. I did that, and the install completed with no problems....

Good luck!

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1  
Indeed, changing the date to the date of the download make it work, I recommend using Wikipedia to check the release version in order to change the system date. – Rodrigo Polo Mar 11 at 8:34

If you are confident in the integrity of your installation media, you can use the terminal to bypass this message completely. The below instructions are for installs performed via a bootable USB stick:

  1. Open the terminal:
  2. Enter: installer -pkg /volumes/Mac\ OS\ X\ Install\ DVD/Packages/OSInstall.mpkg -target /Volumes/"XXX" where XXX is the name of the disk you're installing to.
  3. Wait for the installation to say it's complete. You will not see any sort of graphical progress display.

This allowed me to install El Capitan a couple of weeks ago. I didn't have any internet access at the time, and my Mac had a completely empty hard drive, so I was very happy that I could force the install to go through.

I suspect that this method could be adapted for live installations, but failing that, consider creating a bootable installer and then following the above instructions.

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Actually there are two known possible causes for this message the show up. One is the obvious corrupted installer. Another less obvious and more tricky cause can be a reset internal clock in the machine, with a resulting date which is previous to the release of the OS installer, what will trigger this message too.

Hope this can help someone.

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1  
And a third just confirmed personally: the clock on the computer has to be set to a date near the date of the download. It may be that the installers just have a timeout built into them so there's likely a range of valid dates but setting the clock to the day of the download worked for me. – Perry Apr 17 at 21:00

I have found the solution for “This copy of the Install OS X El Capitan application can’t be verified. It may have been corrupted or tampered with during downloading” error!

If you have tried changing the date / time / on a startup disk, forget about it... Make sure you have an internet connection about 10Mbps at least. What you need to do are as follows :-

  1. Restart your mac. Press the Shift Key
  2. When you see apple logo, release the Shift Key
  3. You will go into SAFE MODE. Install & Download your OS X El Capitan in SAFE MODE.
  4. Make sure you delete existing 'Install Os X El Capitan.app' in Application
  5. Re-download the updates of Os X El Capitan.
  6. After finish downloading, everything is ready to go. Success rate 100%.
  7. You might experience the progress bar hanging around 80-90%. (Tested to let the progress bar run but no avail.)
  8. Force Restart again. Press the Shift Key
  9. When you see apple logo, release the Shift Key
  10. You will go into SAFE MODE again. Now let it run until you see the login screen!
  11. When you've seen the Desktop, that means everything is perfectly fine!
  12. Restart again and press nothing!
  13. Now you have an updated copy of OS X El Capitan!

** For Upgrades only **

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By the way this is not a date time issue, date is correct on my computer.

I think many people think setting the date to the current date automatically fixes the issue, but this is not the case. You have to remember the date you installed "El Capitan OS X installer.app" into your Application folder. For me, it was around Sept 2015. Right now is March 2016. When I got this error while reinstalling El Capitan OS X, I set the date to today's date (i.e. date 03061225616) and it did not work because I installed "El Capitan OS X installer.app" around Sept 2015 and the digital signature/certificates for my installer had expired by now. Once I reset the date to Sept 2015 (i.e. date 0923020415), the installation worked without a problem.

If you can neither remember nor correctly guess the date you installed "El Capitan OS X installer.app" into your Application folder, then you would have to delete it and reinstall it into your Applications folder so that the digital signature/certficates for the installer is no longer expired.

Also, setting the date manually in the terminal (i.e. date MMDDhhmmYY) worked for me. I heard setting the date automatically in the terminal (i.e. ntpdate -u time.apple.com) works for some people, but not for me. It most likely worked for them because they recently installed/reinstalled "El Capitan OS X installer.app" into their Application folder

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This was exactly my problem. I downloaded the installer in Nov 2015 and setting the date properly (May 2016) would always fail. As soon as I changed it to Dec 2015 it worked great. Thanks so much! – Geesu May 17 at 21:09

you could set the time with the date command, but you have to figure out the crazy format and type it in. There's a much easier way.

  1. Connect to wifi, then
  2. run ntpdate pool.ntp.org
  3. you can verify the time is set correctly by running date. Mine was set to the wrong timezone, but that doesn't really matter.

That's all I had to do to get my install to work.

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I encountered the same issue when performing a clean install on a new hard-drive. Most likely it was caused by disconnecting the battery in order to safely install the hard-drive. After setting the date the install was successful.

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up vote -1 down vote accepted

Here's what I went through. As long as I erased my Mac and "bootable usb El Capitan install drive" installation process complained with verification problem I decided to reinstall "Yosemite" using the built-in recovery disk, then I downloaded installer for "El Capitan" from "App Store". It was not possible to install through the "bootable usb drive" again, so I updated to El Capitan, oddly worked. And finally I erased my Mac and repeated reinstallation for "El Capitan".

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This answer outlines a convoluted process that does not get at the heart of what the problem was or why; not to mention that it is a huge waste of time. – Aran Mulholland Jun 26 at 13:09
    
It's just the way it is. – presscorp Jun 26 at 14:44
    
What a huge waste of time? – Aran Mulholland Jun 26 at 15:33
    
You shouldn't accept your own answer when a different answer is obviously better. – Emerson Farrugia Jul 9 at 5:24
    
The point is that None of the answers were helpful until the date when I found the solution. So at that time I solved it on my own. I didn't check other answers which showed up later, cause the problem doesn't bother me anymore. – presscorp Jul 9 at 5:30

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