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SD Cards Not Recognized on iMac But on a Restart

I try to mount 2 or 3 SD cards on my new iMac (27-inch) through the SD Card slot. However, my computer stopped recognizing them. After that, I found that the only way I could mount the SD cards on this iMac was to restart it with a card in the slot. Any following attempts to read SD cards on the iMac fail until the next restart. Have similar problems with mounting a digital camera via USB and an iPhone. I heard that updating software for Snow Leopard or other apps seemed to fix this. Unfortunately, I've updated all available software updates, but no luck. Any more suggestions for mounting my SD cards? Thanks.

Best Answered by

iBoysoft author Connie Yang

Connie Yang

Answered on Wednesday, November 22, 2023

Have you allowed some programs to automatically open and run every time you log into your iMac? From your description, it seems that certain items stop your SD card from being recognized and mounted by your iMac.

You can go to the Apple menu > System Preferences > Users & Groups > Login Items for a checking. If any items are listed there, select them and then click the remove button (-) and enter your admin password on the prompt to remove them. That is how to stop these programs from working at the Mac startup.

If your SD card is still not recognized and not showing up on your Mac, try to:

  • Reset NVRAM on your Mac. NVRAM resetting can fix some Mac hardware's improper actions.
  • Go to Disk Utility to manually mount the SD card.

If your SD card still can't be mounted on your iMac but shows in Disk Utility, the last way is to try using a data recovery tool like iBoysoft Data Recovery for Mac to get files off it first and then reformat it.


If your SD card not showing up in Disk Utility, check the connections, SD card slot, and SD card itself.

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