Q: iMac won't read SD cards

I'm having the same problem with a new (late 2012) iMac. One SD card reads fine, another only reads when I re-boot??? The one that doesn't work is a SDHC UHS-I. Very strange and irritating.

Is this thread any help:

https://discussions.apple.com/thread/4154436?tstart=150

"Killall Finder" in Terminal. I get to do that everytime I want to use this SD card on my new Mountain Lion iMac.

http://cvil.ly/2011/10/30/imac-sd-card-reader-fix/

The advice in Didjeridooo's link worked for my MacBook Pro.  And if I'm not mistaken, the arrow I've drawn in the photo below points to the switch that gets "stuck."  (it's hard to see because it's hard to take a good photo of it )

Not sure if your still having the problem but I was recently which is how I found this discussion and Im no noob either. I found this vid on youtube which solved my problem for most of my sd cards. http://youtu.be/nbc0l-t3f1Q Hope this helps.

I have the same problem, and it started not too long ago just the same. I have to plug-in my camera every time I wan't to save my pictures to the computer. I tried many different card, no success. I even tried an external SD reader, no success. If I leave the SD card in the reader and do a "restart", then it sees it; by if I pull it out and push it back in, nothing. Very annoying! I'm thinking it probably started after an update, but which one? My Mac is "OS Lion 10.7.5 and I bought it in 2011. 

Hope Apple has the answer soon.

At some point (some software update) this issue fixed itself. My SD cards work fine now on my late 2012 imac.

hurinandThe solution depicted in the video you reference of stopping insertion of the SD card a mm short of all the way works for me in my late-2013 iMac. I also reformatted the SD card in my camera in case there had been any corruption.

I press command + r and re started it at the same time.  In a couple of weeks you will have to do it again, but it worked for me.

Found this on another thread and it worked for me....

thatsfixeditAug 7, 2012 7:48 PM Re: SD Card not showing after Mountain lion Update
in response to connorfitz89

Click on 'Finder' 'Preferences' - tick the box 'external disks'

After I read this I tried it and it worked for me. I put two different SD cards in and it wouldn't read them for me. plus if I put them on my ipad with an adapter it worked. I thought it was the reader on my Mac. Not sure what causes it, but leaving the SD card in and restarting the computer did bring them up. Thank you.

Turns out just inserting it quickly worked for me! Weird.

Thanks a lot - that worked for me.

My imac wouldn't actually restart so I just turned it off using the button at the back then started it again with my camera (with sd card) still connected and turned on. Still didn't load my photos but the sd card icon appeared on my screen so I clicked on it and on the photos in it and dragged them into the photos app and bingo - it worked. Thank you.

Hi guys.

I had the same problem and this guy solved it!!!

Take a look : http://cvil.ly/2011/10/30/imac-sd-card-reader-fix/

I did what he said and then I restarted the computer and everything was back to normal.

Good luck

omg! thanks you just saved me from buying another go pro, because i taught i was broken what a legend!