Chosen Solution
Quickly: Samsung 850 Evo 500GB Installed. I used a bootable usb of High Sierra and a sata-usb adapter. I formatted SSD and installed clean OS X High Sierra. Then using Disk Utility Migration I copied all files, apps and other stuff from machintosh HD to SSD. Before I swapped the drives I booted from SSD externally and it worked like a charm. I then swapped the old Mac HD with the SSD and ran disk utility again. I selected Samsung SSD which was now inside my laptop as the startup disk! So I pressed restart and my MacBook Pro will load the full bar but never actually leave that screen. Sat and waited for 3 hours. Tried repair on drive and had no issues. Started again and still it loads the bar and stays at that white screen with the Apple logo(full bar below). I have read all the posts and i’m Not sure if it’s the cable or a faulty SSD. Mise à jour (13/01/2018) I am finally able to post my results and solution to my issue. @avanteguarde , Thank you for your help. @joesipaq , Thank you for your help as well. After i received my Sata cable replacement, everything worked like a charm!
Your SATA cable may have gone bad.
a) try zapping both the PRAM and SMC https://thenextweb.com/lifehacks/2017/06… b) Try holding down “SHIFT” when turning on the computer. This will clean boot into Safe Mode. This will try to force the OS X to dump all caches and rebuild kext caches. Once in Safe Mode, you should be able to restart as normal. c) you may have a bad Sata cable https://www.ifixit.com/Story/18977/SATA_…
