I bought a 5K iKM 4 months ago, with the stock of 8GB of RAM. I bought 2 x 4 GB extra on Amazon (Crucial Ram). But then, it seems that I can not use the 4 RAM slots at the same time. The iMac does not even start, only displays a black screen.
The Crucial ram sticks work 100% because I tried to remove the original ram sticks, using only the new ones, and that the Mac starts and works properly.
Right now, I run the iMac with 3 of the 4 sticks, so at the moment I have 12 GB of RAM.
I've tried using the 3 best sites, it works. Down 3, it works.
2 slots works too.
But as soon as I insert a 4th ram stick, it stops working
I have reinstalled the SMC and NVRAM. Still no luck
Also updated Mojave at 10.14.2 (latest version)
I would like to see if I can try something before setting an appointment with Apple for this, as it is my main work machine and I have to work on some projects now.
Thank you so much!