Creating a macOS installer on a bootable USB drive provides a convenient way of installing a fresh copy of macOS on multiple Macs, and also allows you to perform a clean installation quickly and easily.

Catalina
If you tried to run your installer recently and unexpectedly received an error that it is damaged and can't be used, then don't worry – keep reading for a simple and straightforward way to fix it.

Why is my macOS Installer Damaged?

If you tried to use a macOS installer in the last few days or weeks, you may have been met with an error message saying something like "This copy of the Install macOS Mojave.app application is damaged, and can't be used to install macOS."

installer
As Apple explains in a newly published support document, the likely reason for the "damaged" error message is an expired certificate. Happily though, the fix is very simple.

How to Fix a Damaged macOS Installer

To fix the damaged installer, you should just download the installer again. Doing so will also ensure that you have all of the macOS updates that have been released since you made the original installer, meaning you won't have to update macOS immediately after the initial installation is complete.

You can find the latest official download links below for the last six versions of Apple's Mac operating system, all of which contain a new certificate that has not expired:

  • macOS Catalina
  • macOS Mojave
  • macOS High Sierra
  • macOS Sierra
  • OS X El Capitan
  • OS X Yosemite

To learn how to perform a clean installation of macOS using the bootable USB drive method, click one of the following links: macOS Catalina, macOS Mojave, macOS Sierra.

Related Stories

Apple Introduces New MacBook Upgrade Program for Business Partners

Monday November 29, 2021 7:38 am PST by Sami Fathi

In association with CIT as the financing partner, Apple has launched a new Mac Upgrade Program for small businesses and Apple business partners that allow companies to easily distribute and upgrade their fleets of MacBooks at an affordable price to all of their workers. As outlined on CIT's website, shared by Max Weinbach, Apple Business Partners can distribute the 13-inch MacBook Pro,...

Best Cyber Monday Deals for AirPods, Apple Pencil, iMac, More

With Black Friday over, Cyber Monday 2021 is now in full swing and you can find many of the same sales as last week on Apple products like AirPods, Apple Pencil, and iPad Pro. In this article we're focusing on the best Cyber Monday discounts on Apple products like these and more. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we...

Cyber Monday: Original Apple TV 4K Drops to $99.99 for Amazon Prime Members

We've been tracking Apple product and accessory deals for Cyber Monday 2021 today, and now Woot is offering a solid discount on the previous generation 32GB Apple TV 4K. You can get this device in new condition for just $99.99 if you're an Amazon Prime member. Note that this sale will last for one day only. Note: MacRumors is an affiliate partner with some of these vendors. When you click a...

Best Black Friday iPhone Deals Still Available

Cellular carriers have always offered big savings on the newest iPhone models during the holidays, and Black Friday 2021 sales have now carried over into Cyber Monday as well. Right now we're tracking notable offers on the iPhone 13 and iPhone 13 Pro devices from AT&T, Verizon, and T-Mobile. For even more savings, keep an eye on older models like iPhone SE. Note: MacRumors is an affiliate...

Best Cyber Monday Apple Accessory Deals Available Today

We started sharing deals on Apple products for Cyber Monday 2021 earlier today, and now we're tracking deals and bargains available from all of the best Apple accessory companies. Similar to Black Friday, you can expect Cyber Monday savings from Twelve South, Nomad, Belkin, Casetify, and many more. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and...

New iPhone SE Reportedly on Track for Release in First Quarter of 2022

Tuesday November 30, 2021 8:08 am PST by Joe Rossignol

Apple plans to release a third-generation iPhone SE in the first quarter of 2022, according to Taiwanese research firm TrendForce. If this timeframe proves to be accurate, we can expect the device to be released by the end of March. As previously rumored, TrendForce said the new iPhone SE will remain a mid-range smartphone with added support for 5G:In terms of product development, Apple is...