Why is my new Crucial MX500 SSD not partition supported?

First, the blog space is answered by volunteers. You'll need to speak directly to the iFixit store to exchange out the SSD to a different one.

You are facing a known issue many people face as they forget the SATA interface has been upgraded a few times from the original SATA I (1.5Gb's) to SATA II (3.0 Gb's) and last update to the standard SATA III (6.0 Gb's).

The standards group had a bit of a dilemma which was the more important direction of compatibility! Taking older standards based drives sticking them into newer systems or the reverse having compatibility of installing newer standards based drives into older systems. At the time it was more common a practice to upgrade the system reusing the older drives as they where more expensive! Which is how the Standard was set. Older Drives supported in newer systems, not the other way.

Even still the drive makers realized they needed to offer a way to allow people to upgrade their drives in older systems. Many offered a jumper to alter the drives data rate to one that was compatible with the older systems. Later on it was done automatically set based on the technology used in Ethernet to auto sense the data rate of the switch ports and even migrated to the Ethernet adapters.

Here we use the term Fixed Speed and Auto Sense to describe a SATA drive port speed. For quite a few years we had both fixed and auto sense HDD's but as the market for upgrading the older systems dried up and the pressure to lower costs many drive makers pulled the Auto Sense technology reverting to Fix Speed at the higher SATA III (6.0 Gb's) rate as there was more systems in use using SATA III now. Likewise the SSD makers where also looking at ways to lower the costs and many also followed!

So with that brief history on SATA lets get into you problem!

Sadly, the Crucial MX500 SSD is a fixed speed SATA III (6.0 Gb/s) drive and you system 13" MacBook Pro 2.4 or 2.66 GHz Core 2 Duo (Mid-2010) is only a SATA II (3.0 Gb/s) so the bottom line here is the drive is too fast for your system.

You need a drive which is able to run with the systems SATA II (3.0 Gb/s) ports I/O There are still a few SSD's that offer Auto Sense which will work Samsung 870 EVO or Samsung 870 QVO

If you review these spec sheets you'll see clearly written

SATA 6 Gbps Interface, compatible with SATA 3 Gbps & 1.5 Gbps interfaces

To add to this here's the Crucial MX500 spec sheet it clearly states SATA 6 Gb/s interface only!

So unless the spec sheet offers a clear listing of multiple I/O speeds Auto Sense its strictly a Fixed speed drive and will only work within a system which offers the Same I/O speed.