My iMac won’t read any Micro SD cards any longer. It can read standard SD cards only.
When I insert the Micro SD card, my iMac comes up with the option to Eject, Ignore, or Initialize it. Disc Utility shows that there is a card inserted but it hasn’t been formatted. The card is FAT formatted. I have rebooted, changed adapters, etc., and nothing has changed. This issue happens on all Micro SD cards. Any advice would be much appreciated!
Since you say that your iMac can read the standard SD cards but won’t work with the Micro SD cards, I think the glitch is your SD card adapter. Which SD adapter are you using? Can you tell me which type of micro SD card are you using？
The SD card reader should be compatible with both the Micro SD card and your iMac. Some micro SD cards for specific devices cannot be used on Mac machines or need the matched SD card adapter.
When the options for ejecting, ignoring, and initializing the Micro SD card show up, have you tried them all or anyone of them? You can click the “Initialize” option and follow the on-screen guide to reformat the Micro SD card.
If you don’t want to lose data on the Micro SD card, you can try to use iBoysoft Data Recovery for Mac to rescue files on the card before initializing it.
Download iBoysoft Data Recovery for Mac and install and open it on your Mac. Select the Micro SD card and click Search for Lost Data, wait for the scanning process to complete, select the files you want, and click Recover to save them to your Mac.