I can no longer open JPEG files in Photoshop Elements 12.1 on Mac OSX 10.10.3. I received the error "Could not complete the Open command because there is not enough memory (RAM)." I even tried creating a 10x10 pixel file, saving it as a JPEG, but I couldn't even open that file.
Thanks for the tip. I deleted /Library/Application Support/Adobe/Plug-Ins/Elements 12/Camera Raw.plugin, restarted Photoshop Elements, and now I can open JPEGs again. The file version for my Camera Raw.plugin was 8.5 (236) - I think it's broken for Mac OSX 10.10.3. Let's just hope I don't need to ever open a RAW file!