Mac Mini - Sandisk Ultra II is not recongised?

Has anyone had any issues with the sandisk ultra ii in any of your upgraded mac’s?

I put one into my late 2009 mac mini today and it wouldn’t recognise it, so after refitting my old ssd and booted back in to OSX I proceeded to connect the Sandisk to a 3.5/2.5 desktop dock I have and it still wouldn’t show up in Disk Utility?

I understand that this mini is SATA2, and the Ultra is SATA3 but I thought they’re backwards compatible, but the fact it still won’t show up in the external dock confuses me, is there any compatibility issues I have overlooked or have I been unlucky and received a DOA?

Thanks for any helpful info

check it with another computer. If it is not detected there as well it is probably DOA

Well I have finally managed to initialise it, however it happened because I placed it in the UPPER sata slot of the mini using my already installed 2nd HDD caddy which has a power connector adapter. This 2nd HDD kit used to house my mechanical ‘storage’ hdd, and the LOWER housed the SSD as is normal on the mini, however when I swapped them it appeared and I was able to begin installation?

I wonder if its a power issue, the old SSD that did work in lower slot is a Crucial M4, Rated +5 VDC and 2 AMPS, whereas the SanDisk is 5 & 1.6 AMPS, but to be clear I don’t understand the numbers and/or if its insignificant?

But like I said, I find it pretty bizarre as to why it won’t work in the lower slot, and although there is a threshold limit with SATA2 using a SATA3 drive, I’m getting 202MB’s Write and 252MB’s Read, which is slower than the older M4?


I just bought an Ultra II 960GB for my mini late 2012 with El Capitan.

Try enabling trim.  I was getting low results, after enabling trim it performed much better but still a tad lower than expected.

Check first if trim is enabled.  If not, enable it.

Remember to do benchmarks before and after.

Did you ever get this to work? I’m having issues, and I just posted some details about my MacBook Pro (and an iMac 27)t hat just would not work.