You can do this while still booted from your USB Drive or media. If your confident the install you just downloaded from the App Store is valid, just use Terminal to force install it. If it still fails with the same error message, proceed to next steps below.įorce Install El Captain Terminal Command In Terminal, type the following command in this format shown in example below date MONTH(02)-DATE(28)-TIME(01:51pm)-YEAR(15) date 0228015315 If it’s not correct, continue with these steps.ģ. If your date is correct, then proceed to the next section below. Cancel out to the installation (If you are still on your bootable image of El Captain). Check the date to ensure it’s right – follow these steps.ġ. This happens if your onboard motherboard battery is toasted. Follow the steps below.Įveryone Says: Check the System Time on MacĪpparently, the system time on your Mac may be off causing the El Captain installer to think your system date is way off.
#Remove install os x el capitan mac os x
You can still push forward and install Mac OS X El Captain. It basically means Mac OS X will not proceed installing a copy of El Captain because it can’t prove its authenticity – even if the installation is ok. This error message indicates the MPKG mechanism for checking the application installer checksum (used for proving the install files are valid and from Apple) files failed. It may have been corrupted or tampered with during downloading. This copy of the Install OS X El Captain application can’t be verified. If you are trying to install a fresh copy of Mac OS X 10.11 El Captain after downloading it from the App Store and you are using a bootable USB drive, you may receive an error message right before the install kicks off.