MacBook Air mid 2012 will not recognize 400gb sdxc is there a restriction card type and size?

Hi Macca180,

Thanks for reaching out here in the Apple Support Communities. I understand that your 2012 MacBook Air isn't recognizing the SanDisk Ultra MicroSDXC 400 GB Memory Card and you are wondering if it's compatible.

I'm glad to help with this.

This article explains that the SDXC card can be used, up to 1TB: About the SD and SDXC card slot on your Mac and I assume you're using a passive adapter for the MicroSD, as described in that article.

If it's not being recognized, you'll need to do some isolation, to see if the issue is with the card itself (by testing in a different computer) or with the SD slot on the Mac (by testing a different card).

Take Care.