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

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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 Sep 29 '18 at 7:56

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 Sep 29 '18 at 8:56
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    @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 Sep 29 '18 at 9:52
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    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 Sep 29 '18 at 9:52
  • Thankyou! This did the trick for me and I'm posting this from Safari in macOS Mojave! :) – user304149 Sep 29 '18 at 21:42
  • Oh, I have an iMac Pro, so maybe there's something in your T2 theory! – user304149 Sep 29 '18 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.


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.

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protected by Community Jan 30 at 12:39

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