aperture not seeing SD card for import
I have Aperture 3.6 with an iMac running OS 10.3.3. My Aperture default is set to automatically recognize a camera when it is connected and to import its photos. Things used to work that way, but no longer. I can connect my camera by USB or insert the SD card into the iMac slot, and I am no longer given the option of importing the photos, although some weeks ago this was my usual way of importing photos. Now
I have to go to finder, open the folder of the SD card and drag the images into Aperture.
I have tried emptying the Finder trash and the Aperture trash. I have tried repairing disk permissions. I have restarted Aperture and have rebooted the iMac. None of these suggestions of others has worked for me.
Any other suggestions?
Aperture 3, OS X Yosemite (10.10.2)