Hi, I'm currently experience this same problem with a Crucial MX500 SSD (500gb) in a early 2011 Macbook Pro 13".
Last October I installed the new SSD without formatting it, and following the Mac instructions I installed de Mac OS in the new SSD and it functioned properly.
4 months later my mac didn't boot and by restarting in safe mode (holding alt/option key) my SSD doesn't show up.
I clicked on "recover system from the internet" and clicked on "disk utility".
Finally the SSD shows up but I can't fix it or repair it and the error is the following:
"Volume verification error. Files system not recognized"
Checking The Partitions Map Scheme it says "Master Booting Register (MBR)".
I'm going to connect my old HD in order to discard this possibility.
Looks like i will have to format my SSD in order to reinstall the OS software, but I will try to connect my SSD via usb-STA cable before in order to save my information as I don't want to lose it in the format.