OSX USB Install Troubleshooting April, 2020 Usually occurs when installing a new hard drive. And Unplugging the battery to put it in. Fix: The installer payload failed signature check During USB install of Mac OSX In Utilities, open up the terminal type “date” press enter I should show the system date, which is wrong, type in : date [today’s dat] in this format month(2 digits) day(2 digits) time( 4 digits- military time) year( 2 digits) Here is our example for April 13th, 2020 at 4:12 pm date 0413161220 04 - is the month 13 - is the day 1612 - Is time in military time (4:12pm) 20 - is the year so type in: date 0413161220 then ENTER (With of course the current date and time represented after date)