My Macbook was slow, and then i've want to make it faster, it is a Macbook Pro from 2011 or 2012, can't remember it. I bought a Samsung SSD 850 EVO.
Firstly what i did, was to take out the old hard-drive, and then i placed the new SSD in it, i made a bootable thumb-drive, with Yosemite 10.10, and then i tryed to boot it from the USB, but i could't install it, because the hard drive didn't show up, because it wasn't formatted. I did that, by taking the old hard drive, inside the Macbook, and used a hard drive dockingstation, to format it, via. disk utility. The hard drive, can only be installed from, the dockingstation, without any issues. I did that, and boot up the Macbook, a Apple logo with a spinning wheel under it, and nothing happens. I tryed everything, used Carbon Copy Cloner, i tryed to make a bootable thumb drive, with diskmakerx.
In recovery, when the SSD is in the dockingstation, i was able to install Mountain Lion, from there, i could boot up fine, no issues. After i place the SSD with a succesfull Mountain Lion, inside the computer, i wasn't able to boot up again, only a Apple logo and a spinning wheel, under it.
I used 4 weeks to make the computer work, i searched all arround Google, Apple.com, and other sites. But i couldn't find any solution.
Please help me :(