Mac OS sierra app is damaged

Step 1. Go to your applications folder.

Step 2. Find the installer for macOS Sierra.

Step 3. Right click on the installer and click "Show Package Contents".

Step 4. Click on folder named "Contents".

Step 5. Click on the folder named "SharedSupport".

Step 6. Delete the file named "InstallInfo.plist".

Step 7. Enter your administer password to confirm.

Step 8. Now open the installer.

If you have reset NVRAM PRAM before the installation, than date and time was been reseted.

Wrong date is one of reason to cancel installation with "This copy of the Install macOS Sierra.app application is damaged, and can't be used to install macOS"
If you are installing macOS using USB, run Terminaland fix System Date using command: date {month}{day}{hour}{minute}{year} <enter>
Example: date 030223592018
Means March, 02, 23:59, 2018

after that select: Install macOS ... again.

It really works for me.

Verify you have your >System Preferences>Date&Time> Set to Automatic

and try again. (If it is already checked then try unchecking.)

delete all previous downloaded copies, and down load again.

I think I have the answer.

Summary

1. Turn off SIP

2. Install High Sierra

3. If you enjoy pain, turn SIP back on.

Detailed steps

1. Restart the computer

2. Immediately hold down CMD+R and release it when the Apple logo appears.

3. Select Utilities | Terminal from the menu bar

4. On the command line type “csrutil disable”

5. On the command line type “reboot”

6. Download and install High Sierra

If you enjoy pain in your nether region, repeat steps one through five, but type “csr enable" in step four. We’ve been running OS X without anything resembling SIP for years and years, so it is probably safe to run without it.

Thank you this fixed my issue on high sierra. i deleted the installnfo.plist and it worked 🙂 i was trying to do a clean install and it kept saying image is damaged, but put the image to a usb and i deleted the installnfo.plist file and then it worked thanks @thubredhal

I'm sorry for my english. I'm from Poland. The sierra is serious software error. At el capitan system save after 4 gigabytes per day, and now you can save 50 gigabytes of data. This shortens the lifespan of an SSD. Every day Sierra stores 50 gigabytes of data ... It is a very serious mistake system that will quickly consume ssd drives. update_dyld_shared_cache process save a lot of data on hard drive...

I was having this issue running off of a Bootable USB drive with a brand new SSD drive installed. I used disk utility to repair everything I could and rebooted but same issue. I then followed these instructions http://www.macworld.com/article/3097533/macs/installing-os-x-what-to-do-when-thi s-copy-of-the-install-os-x-application-c… and while connected to a hardline set the time using the Terminal command ntpdate -u time.apple.com. My install proceeded as expected as soon as I did this.

Did you guys try to make a bootable Sierra installer and tried to install it that way?

Here's a helpful link with El Capitan instructions but it works for Sierra as well, you only need the apply the correct path and name of the installer.

Create a bootable installer for OS X - Apple Support

Step 1. Shut down your computer.

Step 2."Start up from OS X Recovery. To start up from OS X Recovery, hold down Command (⌘)-R immediately after turning on or restarting your Mac. Release when you see the Apple logo." About OS X Recovery - Apple Support

Step 3. Open "Disk Utility".

Step 4. Select your Drive and run first aid.

Step 5. Restart your computer.

Step 6. Open the installer.

Let me know if this work's.

Hi Thubredhal,

I did the below steps you have provided, after doing that also I am getting the error as app is damaged. Is there any other ways to correct this.

Step 1. Shut down your computer.

Step 2."Start up from OS X Recovery. To start up from OS X Recovery, hold down Command (⌘)-R immediately after turning on or restarting your Mac. Release when you see the Apple logo." About OS X Recovery - Apple Support

Step 3. Open "Disk Utility".

Step 4. Select your Drive and run first aid.

Step 5. Restart your computer.

Step 6. Open the installer.

Thanks,

Vinay.

Imagine you have a pice like this in your brand new shiny electrical selfdriving vehicle. God **** it I forgot to delete the .txt file, now the brakes are oooo-oooo!

You now... I give up. After all, what`s the rush? I like El Capitan, at least it works fine. At least doesn`t remind me of a Bill Gates product. Over my mac time I had various incidents with my machine, but AFTER installing the so much advertised piece. It looks this time is different...

Imagine you have a pice of s. like this in your brand new shiny electrical selfdriving vehicle. God **** it I forgot to delete the .txt file, now the brakes are oooo-oooo.

You now... I give up. After all, what`s the rush? I like El Capitan, at least it works fine. At least doesn`t remind me of a Bill Gates product. Over my mac time I had various incidents with my machine, but AFTER installing the so much advertised piece. It looks this time is different...

Step 1. Sign out of the App Store.

Step 2. Restart your computer.

Step 3. Sign back into the App Store.

Step 4. Try to download again.

If this does not work then stop and give detail's on what failed.

If it did work but you encounter the follow message "This copy of the Install macOS Sierra.app application is damaged, and can't be used to install macOS."

Then do the following.

Step 1. Go to your applications folder.

Step 2. Find the installer for macOS Sierra.

Step 3. Right click on the installer and click "Show Package Contents".

Step 4. Click on folder named "Contents".

Step 5. Click on the folder named "SharedSupport".

Step 6. Delete the file named "InstallInfo.plist".

Step 7. Enter your administer password to confirm.

Step 8. Now open the installer.

al_b wrote:

Now... installer OK, your tip works. But after that macos FAILED TO DOWNLOAD. This is sick. Very sick.

If you have an installer that works why do you need another, just make a copy of the one you have.

After deleting the InstallInfo.plist file the installer opens and appears to be okay until it tries to go back to the App Store to download a helper. Then the download fails with the message "macOS Sierra failed to download. Use the Purchased page to try again." There is nothing related to Sierra on the Purchased page.