trying to install a Mac OS on my mid 2009 MacBook Pro 15"

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trying to install a Mac OS on my mid 2009 MacBook Pro 15"

I used the links to download os El Capitan and Yosemite but when I try to boot up my MacBook Pro using a flash drive with the os installer on it it gives me a message that says "This copy of install OS X Yosemite application cant be verified. It may have been corrupted or tampered with during downloading." but I used a link from the apple website to download it and everything went fine and had no issues. I'm using a 15" MacBook Pro mid 2009 model A1286 s/n W80190WQGAX

I'm not able to get into the laptop so I'm going through recovery mode. turning it on and holding option. I'm using a flash drive with os on it because the ssd won't show up when I start the computer up this way. but when I get to where I can click the install OS X I'm able to select the ssd for it to be installed on. once I click install and agree it starts but doesn't load and gives me that error message. please help

MacBook Pro 15″

Posted on Sep 12, 2023 9:27 PM

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Answer 1

Johnb-one

Level 6

9,180 points

Sep 13, 2023 3:04 AM in response to absolumthewanderer

Hi, absolumthewanderer… well, maybe start out by safely ejecting the usb flash drive with the installer on it from your MacBook Pro. Then do a reset smc/pmu and 3-4 pram zaps on startup per this link ; https://www.macworld.com/article/224955/how-to-reset-a-macs-nvram-pram-and-smc.html#:~:text=Intel%20Macs&text=Press%20the%20power%20button%2C%20and,Mac%20to%20continue%20starting%20normally…. Then hold down option key on startup to get to startup manger.. your MacBook Pro from 2009’ could run El Capitan, which is recommended over Yosemite for a few reasons: Yosemite has a large-ish bug in it: Wi-Fi doesn’t work at all in it, but in El Capitan it does… so get a copy of El Capitan installer in .dmg format + the usb stick ( properly Mac formatted) + bootable usb stick installer app ( I used DiskMaker X with no problems-) it works for me) and away you go.. you can get El Capitan from Apple via this link:: How to download and install macOS - Apple Support (CA)

use Safari for this: Firefox and other browsers may work, but you’ll have to “point it/them” to the App

Store to get the download working OK… after you have downloaded the installer, then use DiskMaker X + El Capitan to make usb bootable El Capitan stick, restart MacBook Pro holding down Option key on keyboard to get to Startup manager, plug in USB stick, left+ right arrow keys to select, mouse click or Enter/return on keyboard to confirm/say “yes” then let the El Capitan installer run

John B

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trying to install a Mac OS on my mid 2009 MacBook Pro 15"

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