upgrade blocked - is this terminal?

[agwilliams]

I tried to upgrade my late-2012 iMac from Yosemite to High Sierra, but when I went to the app store I received this message:

This copy of the Install macOS High Sierra application is damaged, and can‘t be used to install macOS.

Is there a solution to this, or do I need to put a new iMac on top of my Christmas list?

 

[krs]

I tried to upgrade my late-2012 iMac from Yosemite to High Sierra, but when I went to the app store I received this message:
This copy of the Install macOS High Sierra application is damaged, and can‘t be used to install macOS.

This is the message I got when the installer certificate had expired.

Couple of comments:
1. Which browser do you use? I found out a short while back that Firefox has problems downloading a macOS, one needs to use Chrome or Safari.
2. I also thought one needed to upgrade to ElCapitan first before being able to upgrade to High Sierra

In any case, with the iMac you have you could upgrade all the way to Catalina, but there are caveats.
Main ones are:
Mojave (10.14.x) works best with an SSD because Apple changed the file system.
Catalina (10.15.x) no longer supports 32-bit applications.

 

[Rod]

I tried to upgrade my late-2012 iMac from Yosemite to High Sierra, but when I went to the app store I received this message:

This copy of the Install macOS High Sierra application is damaged, and can‘t be used to install macOS.

Is there a solution to this, or do I need to put a new iMac on top of my Christmas list?

I'm a bit confused, are you saying the App Store told you the Install macOS High Sierra app is damaged? Or do you mean after you downloaded it you got that message on launching the app?
krs, is correct, that message is often given if the certificate for the app has expired but that should not happen if you just downloaded it from the App Store.

It seems clear from what I have read that the late 2012 iMac does have problems running Mojave so High Sierra is as far as I would recommend you go.

Here is a very handy link from Apple with instructions and links to upgrade the macOS on older Mac https://support.apple.com/en-us/HT211683
Note: If you are using the links that require using a web browser it is best to use Safari as krs has already suggested.

If you continue to have a problem with the El Capitan installer you could try installing Yosemite then upgrade from that to High Sierra.
Let us know how that works for you.

 

[Rod]

This might be helpful too. https://osxdaily.com/2019/10/24/fix-install-macos-application-damaged-cant-be-used-error-mac/

 

[krs]

This might be helpful too. https://osxdaily.com/2019/10/24/fix-install-macos-application-damaged-cant-be-used-error-mac/

That is a great link.
I had tried method 2, removing the InstallInfo.plist, several months ago with the USB Mojave installer I had made (that no longer worked) and that resolved the problem for me.
On line, when one searches about this issue, method 3, resetting the date on the Mac is often mentioned as a solution, but there are also comments that this might create problems.
I think downloading the installer again from Apple is the best approach, the certificate of the current download is good for about 10 years.

 

[harryb2448]

Best solution is to download the Installer whilst it is the current operating system. It will just sit in your Applications folder until (or if) you are ready to upgrade.

 

[MarkAllread]

Here's another good link for you if you are comfortable with the terminal. If not, be vewy vewy careful ;-)

How to Download Full MacOS Installers from Command Line

Mac users can download full complete MacOS installers directly from the command line. This is an incredibly useful feature particularly if you want to build USB boot drive installers, you manage mu…

osxdaily.com

 

[Raz0rEdge]

High Sierra is an absolute pain to install, lots of issues with this damaged installer or issues with APPFS and other things. When I had tried to do re-install of High Sierra on my 2009 iMac, I tried to do it with a USB installer and it took at least a dozen times with lots of random tinkering to get it to work.

 

[ferrarr]

Do you have macOS High Sierra already downloaded, or did you just download it now?

 

[macnicol]

I tried to upgrade my late-2012 iMac from Yosemite to High Sierra, but when I went to the app store I received this message:

This copy of the Install macOS High Sierra application is damaged, and can‘t be used to install macOS.

Is there a solution to this, or do I need to put a new iMac on top of my Christmas list?

The easiest solution is to check the download date or version date of the installer dmg/pkg. Then set your system's date to a month or so close to the date of the file. This tricks the pkg and lets you install with it, Simple. I have used this many times on past systems.

 

[agwilliams]

Thank you for your help, gentlemen, but I finally came to the conclusion that it was time to cut through all of the issues and go for a radical solution - so I've just bought a new iMac and (as Christmas is approaching) pushed the boat out for a 27 inch model. Wow - what a screen! Not just iMac, but iMax!

 

[Raz0rEdge]

That's one way of dealing with it, my kinda solution. I approve!