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S. Meijer Level 1 (0 points)

Why is my Mac not willing to read the 128GB SD-card? Does anyone have a clue?

Many thanks for your help.



iMac, Mac OS X (10.5.8)
  • BDAqua Level 10 (122,276 points)

    Hi Sadhna,


    Do you know what format it is?


    Does it show up at all in Disk Utility?

  • S. Meijer Level 1 (0 points)

    Hi there,


    Thanks for your reply. I don't know where to look at for your further questions so I made a printscreen of the message which I get. Does this help?




  • BDAqua Level 10 (122,276 points)

    Sadly the pic doesn't show, perhaps you dragged & dropped it, that looks like it works until you post it, to get a pic to show, click on the tiny camera icoon, browse to the pic & submit/upload it.

  • S. Meijer Level 1 (0 points)

    I am afraid it's to small to read it.

    Could you please give me a few more instructions: like where to look at it for the format?

    the SD-card doesn't show at all in disk utility. I have to initialize it first..... leading nowhere at all!

    And than the picture belows follows.

    Afbeelding 1.jpg

  • BDAqua Level 10 (122,276 points)

    OK, it shows MBR, Master Boot Record there.


    If you highlight the partition below that does the blue Mount button become available... maybe Montageplatte???

  • S. Meijer Level 1 (0 points)

    Unfortunately, the button doesn't become available.

    FYI: at software version OSX 10.7.5 (Mac Book Air of my husband) this SD-card can be opened. I need it, however, on my Mac which is another version.


    Maybe this helps?

  • BDAqua Level 10 (122,276 points)

    Ah, highlight the Partition again, click the blue Info icon, does it say exFat, which requires 10.6.5 to read/write?


    Is this card used for other than  the 2 Macs? Like a Camera or PC?

  • S. Meijer Level 1 (0 points)

    Thanks again for your support, really appreciate this! I send you two other pictures with the details I have found. Instead of exFat the info shows MS-DOS (FAT). However, if I change the volume into 16 partitions than the structure changes into MAC-OS Extended (Journaled). Is this perhaps the key to the solution?!


    And yes this card is being used for three computers totally: one Mac, Macbook Air and Pro and a camera as well. This goes for all our SD-cards which we use by the way.Partition changed.jpgPartition.jpg

  • BDAqua Level 10 (122,276 points)

    Most Cameras are not going to understand or work with Mac OS Extended Format.


    To see what Format it is, highlight the icon at the red arrow, then click on the icon at the blue arrow. The Structure pointed at by the green arrow is where you could choose it to be if you erased or reformated it...


  • BDAqua Level 10 (122,276 points)

    Your Mac should understad MS-Dos, so I think MBR must be the problem, but it's likely the Camera may need that.

  • S. Meijer Level 1 (0 points)

    I think you are right: MBR is the problem because the camera needs it!


    Despite all our mutual instructions and efforts we haven't been able to solve this issue. The secret is hidden in the fact that the 128GB is an XC I version and our other 32GB SD-card is an HC I version which is indeed compatible with our lower version IMac and MacBook. The difficulties arise when there are movies recorded in both the SD-cards; then all of a sudden none become accessible. We have erased the movies from the 32GB SD-card after which we could use the card for the pictures again. The 128GB is not at all accesible for the lower versions of the Mac's even after erasing everything!


    Our questions:

    • Can the 128GB (XC I version) only be used for recording?
    • And after making pictures at the same time does it become unsuitable for copying these to lower Mac versions like my Mac?!
    • Is the conclusion then perhaps that only higher versions like my husband's Mac Book Air (OSX 10.7.5) are suitable for these 128GB SD-cards?
  • Gary Scotland Level 6 (12,818 points)

    SDXC cards require  Mac OS 10.6 or later operating system to work, therefore your cards cant be used with your 10.6 machine.

    These cards are a relativly new format and therefore reqire a relativly new operating system for them to be used.

  • S. Meijer Level 1 (0 points)

    Thanks a lot, Gary!

  • S. Meijer Level 1 (0 points)

    I think the problem is clear to us now so I will close this chapter. Thank you so much for all your instructions and support. Take care!

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