Prohibitory Sign after install Sierra on new SSD
I own a repair shop, one day a customer want to upgrade his MacBook Pro 2012 from HDD to SSD, he brought his own ssd it's Toshiba OCZ tr150, after installation finished it runs smooth and he brought his MacBook home. Then on the next 2 days he called me that the OS failed to boot, shown a prohibitory sign on boot. I tried to re-install the OS it worked and then the next 2 days he called again with the same problem. I wonder why this is happening.
FYI i already changed the HDD cable but the problem still occur, anybody have the same problem? I would like some insight, thank you before
sorry for bad grammar, english is not my main language :)