\"This copy of the Install OS X Sierra application can't be verified\"

#failure#fehler#hilfe#macintosh#neuinstallation#nicht-verifiziert#osx#reinstall#support#systemzeit

Today I wanted to hand my old Mac over to a friend, and as a conscientious user I of course reset everything to zero first. So I quickly created a bootable USB stick via

sudo /Applications/Install\ OS\ X\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/USB/ --applicationpath /Applications/Install\ OS\ X\ Sierra.app/ --nointeraction

formatted the HDD and started the installation. Then the shock:

"This copy of the Install OS X Sierra application can't be verified. It may have been corrupted or tampered with during downloading."

After a lot of googling I came across the tip that the system time might be wrong. So, open the terminal (boot from the CD -> Utilities -> Terminal) and quickly enter

date

Result: the system time was off by more than 5 minutes from the actual time! During the installation process you can correct this with the "date" command by passing the desired date / time as the first parameter in the format mmddHHMMyyyy.

date mmddHHMMyyyy

mm = month
dd = day
HH = hour
MM = minute
yyyy = year (four digits)

Example: 013015442018 = 30.01.2018 - 15:44

When you change the date, keep a possible time zone shift in mind. If you have CEST set as your time zone and you're in Germany, everything's fine. If a different time zone is set, you have to adjust your date / time according to the selected time zone. You can find the time zone by clicking the little flag in the top right corner.