Macbook Pro 13" 2015 with OS X Yosemite on board. I've been trying to install OS X El Capitan, but always get the following message: "This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading."
By the way this is not a date time issue, date is correct on my computer.
How can I fix this? Who knows the solution, please help.