I've been trying to upgrade my Mac from High Sierra to Mojave, but I keep getting the error below.

enter image description here

I rang Apple support and they told me to wait a while and try downloading it again from the App Store. I've now done this 2 times and continue to get the same error.

I spoke with Apple again and they said to wait a while and try installing it again. It's now been two days and I've rebooted my Mac a number of times, and have attempted installation many times.

I also tried installing all other software updates in case that was a factor. They all updated fine without any problem. The only thing I can't do is get the Mojave installer to run because it is apparently "damaged".

Maybe this is the universe telling me not to upgrade and I should give up, but now I'm here to ask you good folk.

Can someone kindly suggest other options for me?

  • Firstly, welcome to Ask Different! :) I've added an answer for you, but if you get the chance it'd be good if you could clarify the exact model of Mac you're using - especially if my answer doesn't solve your problem.
    – Monomeeth
    Commented Sep 29, 2018 at 7:56

6 Answers 6


The first thing I would try is resetting the System Management Controller (SMC) of your Mac.

Since you don't specify the model of Mac it's not easy for me to set out the steps you need to take, so I refer you instead to this Apple Knowledge Base article: How to reset the System Management Controller (SMC) on your Mac.

Make sure you read through the article and follow the steps for your Mac carefully.

  • 1
    I am curious to know if this is resetting the SMC is just a general tip to fix things (akin to a reboot) or is there a specific "thing" that can be fixed by resetting SMC than can make the installer work?
    – Nimesh Neema
    Commented Sep 29, 2018 at 8:56
  • 1
    @NimeshNeema Well, resetting the SMC (like resetting the NVRAM) are both good general tips for fixing things, but in this case I've suggested this as I came across the exact same error three times in the past week (one on an iMac Pro, the other two were 2018 MacBook Pros), and after a process of elimination I found that resetting the SMC did the trick on all of them!
    – Monomeeth
    Commented Sep 29, 2018 at 9:52
  • 1
    I admit on the face of it this solution doesn't make sense (as you probably know, the SMC is mainly about power, thermal, sensor and lighting management), so if anything resetting NVRAM would make more sense. However, my working theory is that all three Macs have T2 chips in them, so maybe resetting the SMC has something to do with that (far from proven obviously - 3 Macs is hardly a valid sample). But if I come across a few more examples I'll be letting Apple know (for what it's worth)! I hope the OP comes back and let's us know what Mac they have! :)
    – Monomeeth
    Commented Sep 29, 2018 at 9:52
  • 1
    Thankyou! This did the trick for me and I'm posting this from Safari in macOS Mojave! :)
    – user304149
    Commented Sep 29, 2018 at 21:42
  • Oh, I have an iMac Pro, so maybe there's something in your T2 theory!
    – user304149
    Commented Sep 29, 2018 at 21:43

go to the applications, and delete the "install macOS Mojave" file, and then you are able to re-download the file in app store. Just try to download it again. That's all.

  • 1
    awsome answer. works perfectly. Thank you very much :) Commented Oct 24, 2019 at 21:30
  • 5
    This didn't work for me. After deleting and 6 GB re-download, I get the same error.
    – Bill
    Commented Jan 14, 2020 at 5:42

After searching for how to fix this after I had erased my drive leaving me with no system, I have figured out how to fix it without having to download the installer again.

What I did:
With a USB installer connected, restart your Mac and hold the Option key to get to your boot selection screen.

Select the Install MacOS Mojave option.

If you do not disconnect, the system will update its clock from the servers.

After disconnecting, click on Utilities > Terminal to open the Terminal.app.

In the command line, navigate to the root directory with:

cd /

In the root directory, list the contents.


You should see the directory contents including Install MacOS Mojave.app. You need to find out the date of that file. Type:

stat Install\ MacOS\ Mojave.app

(The name may be different but make sure you use the one shown on your screen and don't forget to escape the spaces with a forward slash.) It's likely that there is only the one file named like that so an easier way to get it is by typing:

stat Install

and hitting Tab to auto complete the filename. This should show some information of the file including a couple dates. You now want to set the date of your system to a date around when the installer was created therefore marking the certificate "valid". Lets say the date it was created was Mar 20, 13:45 2019. We will set the date to the day before, Mar 19, 13:45 2019. The format for setting the date is important and it is:


No spaces. A single long number. To change the date to Mar 19, 13:45 2019, use the date command.

date 031913452019

Confirm the date change by running the date command alone. If successful, quit Terminal to return back to the main screen and try installing again. It should work this time.

When it gets to the stage of install asking you to enter your wifi or network information, it is okay now to do so as the installer has already been confirmed good.

I hope this is able to help others stuck in a similar situation.

  • Nov 2019, this worked for me!
    – Jake N
    Commented Nov 26, 2019 at 22:20
  • 1
    According to osxdaily.com/2019/10/24/…, this works because certificates have expired in the installer.
    – mwfearnley
    Commented Dec 10, 2019 at 14:14
  • 1
    As of 2020, this is the correct answer. As @mwfearnley points out this is because the certificate has expired. Commented Apr 23, 2020 at 6:40

The solution that worked for me is described in this answer on the Apple support forum by rayhaanalykhan:


  1. Go to your applications folder.
  2. Find the installer for macOS Mojave.
  3. Right click on the installer and click "Show Package Contents".
  4. Click on folder named "Contents".
  5. Click on the folder named "SharedSupport".
  6. Delete the file named "InstallInfo.plist".
  7. Enter your administer password to confirm.
  8. Now open the installer.
  • Did not work for me (trying to go from El Cap to Mojave in one jump). used the same Mojave installer I used to build a couple of successful Hackintoshes about a year ago; copy preserved on a thumbdrive. Deleting InstallInfo.plist didn't fix the problem.
    – De Clarke
    Commented May 13, 2020 at 21:26

It’s possible, but rare, for the network to corrupt very large downloads. Try downloading at a different location, perhaps using wired Ethernet. Or download the installer to a different Mac, and copy the data over to your Mac using an external HD.


Is the machine connected to the internet? I had this error and entering my WiFi credentials to connect resolved it.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .