HELP mac stopped recognizing my camera

I have been using my iMac for at least half a year now with my Canon Rebel XS 10.1MP Digital SLR Camera with EF-S 18-55mm f/3.5-5.6 IS Lens (Black). I have had no issues previously. The last time I tried to upload photos from my camera, however, the Mac would not recognize it. The red light on my camera would just start flashing and nothing else would happen. I even tried pulling out the memory card and plugging that into the card reader on my printer and the computer would not even recognize that. I have tested both the card and the camera on my windows laptop, and they are both working fine. Any clues as to what could be causing this problem or what I could do to find out?

What format is the memory card using? You can check it in your Windows computer from either the Windows Explorer or My Computer. If the memory card was somehow reformatted to NTFS, that might be the reason. Memory cards are formatted as FAT from the factory.

Regards.

update

I had my camera plugged into the Mac when I had to go do something else. When I came back the Mac had finally recognized my camera and was prompting me to upload photos like usual. I am glad that it is working, but still wondering why it would have taken so long to come up? I hate trying to compare the Mac to my windows laptop, but it came up right away on the laptop. Is there some sort of setting I might have screwed up on the Mac?