MacBook Pro 13-inch, Mid 2012 Ignored wiping the mac HD as the video shows 1:53pm - confirm time machine backup, download OpenCore Legacy Patcher 1:57pm - gather tools, make a sandwich (Tools: iPad (to watch video), spare power cable, USB key) 2:04 - resume process; erase USB stick 2:08 - pause video. OpenCore download doesn't match what I'm seeing in the video; go back and read guide on OCLP. 2:12 - return to installer. Follow through window prompts. 2:14 - process now roughly matches video. Downloading MacOS Monterey. Will sync with video shortly. 2:24 - still waiting ... ... ... 2:27 - asked to create an installer. Starting that process... 2:29 - it's taking a while, throwing on Deep Space Nine (I'm on season 1, episode 8 of my rewatch. - Odo/Quark are perfect from episode 1. Well, Odo needed some work. But by this point (E8) Odo is very nailed down. 2:53 - still setting up the USB ... ... ... 3:05 - started a mini-zine, inspired by the "Cool Bloggers Walking Club" 3:45 - "validating installer integrity" - almost there! 3:50 - still validating. Taking a break to pick up car from garage. 4:48 - success! But it's dinner time. 4:56 - install OpenCore to this disk? Yes. This is the same as the build & install step in the video. 4:58 - process finished. At this point it's time to shut down and boot from USB. Taking another break. Elapsed time: 3 hours, 5 minutes. 8:33 - back at it. Consulting the video again - it says to start the MacBook while holding the option key to boot from USB. First though - I missed the suggestion to copy the patcher to the USB key so I'm doing that. 8:43 - okay - back at it with my tea. Have launched to the boot screen. Installing... 8:45 - moment of slight trepidation - had to confirm with a Google search that picking "install macOS Monterey" wouldn't delete my data. **This is the point where I opted NOT to wipe the hard drive** 8:47 - Installing...back to the Jays game for a bit. 9:38 - installer seemed to finish but there's still a progress bar below the Apple logo. No more estimated completion time. 9:45 - nothing new here. Keeps alternating between Apple logo loading & going back to the install screen. New this time - seeing a completion bar on percentages. 10:05 - we have a startup chime! Back to Apple loading screen, though. 10:07 - startup chime again. 10:15 - we have the desktop! "About this Mac" showing Monterey. Going back to the video to complete the process (patching) 10:24 - installing OpenCore patcher to Macintosh HD, not finishing tonight as I'm tired. Elapsed time: 1 hour, 51 minutes Next day 4:39pm - started up MacBook. Get a folder with a question mark on it. Hmm. Booting from USB again. This seems to work. At least no question-mark folder. Apple logo is loading. 4:45 - there's an update to OpenCore, so doing that. 4:47 - seems like OpenCore ran some install / patching stuff on its own so now restarting the machine to see if it will boot on its own. 4:48 - seems promising! I had to click on the mac HD image, no question mark file folder. This part might be automatic but I'm not sure? 4:50 - success! MacOS has launched successfully. Opened OpenCore again to finish post install root patching. Error though..."failed sanity checks". Need to research this. 5:01 - found a video that fixes the problem, but it's time to cook dinner. Elapsed time: 22 minutes 7:30- followed video instructions to try to get an upgrade to fail. Side note: the system does start on its own without intervention. 7:39: Success! The patches are being installed. 7:43: we're all set. An update to the next OS is available but will see how Monterey runs first Elapsed time: 13 minutes. Resources: [How To Install Monterey on a 2012 MacBook Pro - YouTube](https://www.youtube.com/watch?v=fyFqkbmKP68) [OCLP SystemVersion.plist BuildVersion Mismatch Error - How to Fix! - YouTube](https://www.youtube.com/watch?v=gbMYXwUmmfw) [OCLP 2.0 - Ventura 22G830 - Sanity check failure during root patch : OpenCoreLegacyPatcher](https://old.reddit.com/r/OpenCoreLegacyPatcher/comments/1fhsmac/oclp_20_ventura_22g830_sanity_check_failure/)