Invisible drives in High Sierra
History. MacBook Pro acquired with fault, flashing folder on boot up - will only boot from original 500MB hard drive in external caddy via USB. When connected to internal SATA cable HDD is not detected by OS.
Action. Purchase logic board to SATA HDD cable twice - neither of which made any difference. Purchase SATA 3 120GB SSD, install as primary drive - not detected. Clone new SSD into boot disk put in USB caddy - OS detects external SSD and boots up. Replace DVD drive on MBP with caddy - install original 500 GB HDD as secondary drive and SSD in primary drive - neither are detected by OS. Run ADS from OS (logic board diagnosis) result was no problems found.
Overview. Not faulty SATA ribbon cable. Not faulty HDD or SSD. Logic board appears to be working (flashing folder detected and ADS diagnosis).
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