My MBP freeze on a Back-Up after having installed a SSD
ssd
I'm having a MBP (mid 2012, 13 inches), and I changed my HDD for a Samsung V-Nand SSD 850 EVO. I had created a back-up with my External G-drive. Now, the screen freeze since a good while.
Question : What do I have to do to fix this problem?
re 1: hard to say - if you can spare the Money you should go for the 850 bc. of a (probably) better Garbage Collection (see #3), else go for the 840.
re 2: The best tutorial for replacing the optical drive with a harddrive (or SSD) can be found at iFixit.com, f.e. this one. You should search for the Tutorial for your model, the link i posted is probably not for your model.
re 3: There is a hot discussion going on if Trim should be enabled or not and if that is a bad thing. Fact is, Apple has Trim Support enabled only on its own OEM SSDs and disabled it for third party drive. There are Tools to enable TRIM Support, but it could be a not necessary bc. of a better Garbage Collection within the SSD Firmware (see this article and this Article). For general Infos i recommend this Article from Samsung
BTW, to create a homemade Fusion Drive you need to use the 'Core Storage Volume' Command. You can look it up with
man diskutil
look at the 'coreStorage' section. There are some tutorials for creating a homemade Fusion Drive, but it's a very painful process.
Best Answer
Try to macOS Recovery from Internet.
https://support.apple.com/en-us/HT201314
With a LAN cable/ WiFi.