I’m new to Raspberry Pi, but was able to get Raspberian booted, so I moved on to the REAL reason I’ve joined the Raspberry gang… emulators!
I have formatted an 8gb card, DL’d RetroPie v2.6 for my Pi2, wrote it to my SD, ejected and tried to boot but the screen didn’t recognize anything. (I put my NOOBS/Raspberian back in and it worked, so doesn’t seem to be a hardware issue)
I tried re-downloading the file. I tried just drag-and-droppings vs. using the Writer tool. I tried removing the .gz from the end of the filename so the file would register as a .img file and not a .gz file.