My MBP freeze on a Back-Up after having installed a 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?
Try to macOS Recovery from Internet.

https://support.apple.com/en-us/HT201314

With a LAN cable/ WiFi.