Mac OS sierra app is damaged

"FAILED TO DOWNLOAD"?

Now it won't download again, keeps telling me to go to the Purchased tab but it's not there.

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.

When the installer runs it checks the download.

You just said that the installer is OK, you're not making much sense, but Good Luck.

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.

Did you try?

Step 1. Delete the installer.

Step 2. Sign out of the App Store.

Step 3. Restart your computer.

Step 4. Sign back into the App Store.

Step 5. Try to download again.

Just tried those steps again, after an hour of downloading got the "damaged" message again.

I'm in the same boat. I even tried using an installer I used to install Sierra on the two other Macs I own and it gives me the same problem. I don't think there is really an issue with the file that was downloaded. There is something on the particular computer that is causing the issue. I wish I knew what that something is.

My 2012 MacBook Air and 2011 iMac are both having this issue. On a possibly related note, neither will mount an external cd drive since El Capitan (Tried both Apple USB Super Drive and LG SuperMulti Blade on both) even though an inserted disc shows up in Disk Utility as "Uninitalized" (Yes, the genius programmers that ruined Disk Utility also can't spell).