Original post by: Charles Thiele

Text:

This happened again with an Apple Store upgrade of El Capitan here in 2019, which is really incompetent behavior on Apple's part.

I fixed it by setting the system clock in terminal to 12-31-2015 using terminal once it was stuck in its upgrade loop, which allowed it to continue despite its expired certificate in the upgrade image.  It resync'd the clock back to the normal time during the upgrade process.

Status:

open