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3 hard drives from mac pro 2008 which died won't mount when connected to macbook pro 2014, High Sierra, nor macbook air 2022, Sequoia, not even wwhen booting 2014 to yosemite or mavericks usb, disk util sees master boot record but not GUID partition. strange that it is same for all 3 drives when mac pro was running ok, fan got too noisy, shut it down, tried restart several months later no monitor action. pulled drives, no mounting. Could they all have had partitions corrupted simultaneously or do older macOS drives need something else to mount?
 
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