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ExFAT microSD card "not readable by this computer"

yashrg

yashrg

macrumors regular
Original poster
Feb 21, 2008
138
13
I am having some issues with a microSD card that I use with my security camera. After the camera formats the card and records footage on it, I cannot plug the card into my Mac Mini or MacBook Pro and view the files that were recorded.

The first prompt I get says that the disk I attached was not readable by this computer. The first two options I get are Ignore and Eject(There's also initialize). If I choose ignore, I am able to see the disk in Disk Utility. Disk utility shows that the format of the volume is ExFAT. However, Disk utility is unable to perform first aid and repair the disk to be usable.

I can only format the card from Disk Utility. However, after I format the card as ExFAT, when I insert it into my camera, the camera says it needs to format the card again to be usable.

Has anyone else run into a similar issue? What are some ways I could read the card on my Mac to be able to get videos off of it that the camera will record?
 
yashrg said:
Has anyone else run into a similar issue? What are some ways I could read the card on my Mac to be able to get videos off of it that the camera will record?
Click to expand...
It is probably due to the allocation unit size the camera uses when formatting ExFat. The Mac is finicky about ExFat allocation unit size. If your camera and macOS are at odds with each other over ExFat allocation unit sizes, the disk won't mount. You might need some third-party software to mount the camera formatted ExFat disk on your Mac.

I've got this bookmarked because it was invaluable information some years ago...
https://www.reddit.com/r/MacOS/comments/p7ii0i
 
Big may have the answer above, but I was wondering...

Does your Mini have an SD card slot (and were you trying to use it)?
Does your MBP have an SD card slot (and were you trying to use that)?

If so...
Do you happen to have a USB card reader around?
Could you try that instead?
 
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Fishrrman said:
Big may have the answer above, but I was wondering...

Does your Mini have an SD card slot (and were you trying to use it)?
Does your MBP have an SD card slot (and were you trying to use that)?

If so...
Do you happen to have a USB card reader around?
Could you try that instead?
Click to expand...
Trying an external reader is a good idea. Also, not all "SD" cards are the same. There are 3 variants; SD, SDHC, and SDXC. While and SDXC reader can read both of the other two, an SD reader can only read SD cards and an SDHC reader can read SD but not SDXC. Without knowing exactly which Mac Mini and MBP the OP has we can't know what card specs they can read.
 
Fishrrman said:
Big may have the answer above, but I was wondering...

Does your Mini have an SD card slot (and were you trying to use it)?
Does your MBP have an SD card slot (and were you trying to use that)?

If so...
Do you happen to have a USB card reader around?
Could you try that instead?
Click to expand...
I used the SD card reader on my CalDigit dock with my MacMini. On my MacBook Pro I was using the built in slot. I couldn't find my USB card reader earlier, but I have located it and can try it out with that today.
 
Thanks for the help guys. I ended up formatting it as FAT instead of ExFAT and seems to be compatible both ways.
 
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