Chosen Solution
I used SuperDuper to erase and install my dupe OS from MacBook Pro 2010. This mac kept crashing from the old CPU. Do I need to do a clean install of High Sierra then Merge to prevent any crashing problems?
I don’t use cloning apps any longer as they just pass the problem from one system to another! I would pass on High Sierra and instead go directly to Mojave as its just better. Best to create a bootable OS installer USB thumb drive following this guide: How to create a bootable macOS Mojave installer drive But you have another issue which you may not be aware of: If you’ve got an old macOS install image, it will probably stop working today. You’ll want the OS image from here: How to upgrade to macOS Mojave jump to step 4. Make a TimeMachine backup of your 2010 MacBook Pro HD or just use it connected via a SATA to USB adapter cable or just connect your 2010 system via a FireWire cable to your 2012 system after first booting it up under Target Disk Mode by starting it up using the T key Reference: Mac startup key combinations
