Chosen Solution
Hello, I am trying to install a fresh copy of OS-X Mavericks on my 13” MacBook Pro. I did a bootable USB, but every time I tried to install the OS, it says : “impossible to verify this copy. It has been damaged, or altered during the installation. I tried a different USB, same issue. So I went to the historic of the installation program. It says Error : CSSMERR_TP_CERT_NOT_VALID_YET. Would you have any ideas to help me to have an OS :) Thank you for your help !
It’s probably a time and date induced error because of installer certificates expired. You should try take your clock backwords, but you’ll need to do it from the terminal if you have no OS on your Mac. You can get the correct syntax instructions from here: https://bensmann.no/changing-system-date…
Here’s a bit more info If you’ve got an old macOS install image, it will probably stop working today! Apple did release updated macOS’s for Sierra, Hight Sierra & Mojave releases. Sadly, the older ones were not updated. You’ll need to back date your systems Date & Time setting to a year thats within OS release window.
Follow the guide @arbaman has linked to.
