Sat. Dec 14th, 2019

Due to certificate expiration, old macOS install image cannot be installed today

1 min read

If you still keep the old macOS installation image, then, unfortunately, to tell you that these images may stop working after today. This is mainly due to the fact that the certificates in most installation images will expire after today, making these images unusable.

“A few Mac admins noted that the primary certificate, and the intermediate certificate, used to sign many of their packages, was going to expire on October 24, 2019 (which happens to be today).”

This means that when you want to reinstall the old version of the macOS system, all macOS USB bootable USB flash drives pre-installed with non-Catalina may not work properly, so it is time to update your installation image.