The most common reason is using an old installer whose certificate is past its expiry date. Other reasons include a corrupted download or missing key files, like InstallInfo.plist. In this article, we will discuss different ways to solve this error.
1. Change Your Mac’s Date
The error appears because the installer’s certificate has expired. You can often solve this by setting your Mac’s date to a time before the certificate expired. To do this, you need to make sure your Mac is completely disconnected from the internet, otherwise it will automatically update the date and time from Apple’s servers, which would defeat the purpose of this fix. Once you set the correct date, the installer should be recognized as valid.
2. Delete the Property List (.plist) File
Another way to solve this is by deleting the installer’s property list file (.plist). These files store settings and preferences for apps. In this case, the installer’s .plist file might be corrupted or outdated. Deleting it can clear the error, but you’ll need your admin password to do it.
3. Reset Your Mac’s SMC
The SMC (System Management Controller) controls many important functions on your Mac—like power, sleep, and other system management tasks. Sometimes, resetting the SMC can resolve unexpected issues, and it’s helped other users fix this particular problem as well.
3.1. Macs with Non-Removable Battery
3.2. Macs with Removable Battery
3.3. Mac Mini, iMac, and Mac Pro
4. Delete and Re-Download the Installer
If none of the above fixes work, the best solution is to delete your current installer and download a fresh copy from the App Store or Apple’s website. New installers come with up-to-date certificates, so you shouldn’t run into this issue.
