Lately I've found that LR crashes frequently on clicking the 'Import' button, usually right after startup or after sleep. Also, LR no longer starts the Import module automatically when I insert an SD card and it no longer recognises 'new' images, instead it ticks every image for import whether I have previously imported them or not. Very frustrated with CC at the moment.
What is your exact version of LR as well as your OS and version?
In the import, did you have checked to not import duplicates - this is what hides and makes them grayed out?
In the LR preferences, did you set it to show the import upon detection of a card?
LR is the latest version 2015.8 release, OS is the latest MacOS Sierra 10.12.1.
In Import I select and check New Photos only, in Preferences I have card detection checked.
It all used to work fine, but now it doesn't.