I noticed that my photos were syncing perfectly between my macbook air, iPhone 6, and iPad. But my office iMac (20", late 2006) is not up to date. I tried to click on iCloud on the iMac. The message says "Loading iCloud", but the colored wheel just turns and turns without loading it. I did a restart but got the same result. Possibly can anyone tell me what to do next? Thanks in advance.