erase the original user's data and put in your own info.
Clone the USB disk with CCC to the Mac you're trying to upgrade. Clone the other Mac's HD on a USB disk with CarbonCop圜loner, making sure the clone is bootable (include a working copy of CCC in the process). find a computer with installed MacOS 10.11. The only solution that worked was complicated and klutzy: 1. Another error message popped up, and said that my installation file was 'probably corrupted' (freshly donwloaded from the Apple Store). Setting back the date to 2015 did not work for me.
