Put them in the right way
Seriously though, I bought mine from Crucial for my late 2010 iMac, which worked fine. They can be a bit tricky to fit, so just make sure it's seated properly and don't force it.
When you say that none have worked, what do you mean? Is the system not booting? Is it crashing shortly after? Is it simply not recognizing the RAM?I purchased so many sticks none have worked. All were MAC Certified. Can anyone advice?
When you say that none have worked, what do you mean? Is the system not booting? Is it crashing shortly after? Is it simply not recognizing the RAM?
Are you fully replacing the RAM that came with your computer, or are you adding on to it?
Just a note, the whole "Mac compatible" thing is a marketing gimmick that companies use to increase their prices. There's no difference between "Mac compatible" RAM and standard RAM.