Chosen Solution
My MacBook Pro screen freezes and shows black barcodes occasionally. Sometimes it happens with a scary roaring sound, causing me to push the power button immediately. It seems that without switching the power off, the laptop won’t restart itself. It happened the first time after replacing the original 2x2GB RAM with the new 2x4GB RAM and the original HDD with the SSD. See the picture above. MacBook Pro 13" Unibody Late 2011
Remove the ram stick from the lower slot and try the computer. This is a well documented ram issue with the MBP 13” 2012.
I would double check the RAM to make sure it’s seated however in my past experience with a 2012 non retina pro, it had to do with the motherboard. After I dropped mine it constantly had issues like this where it would freeze up and become unresponsive.
