I have a 2014 21" iMac. I use hardly any space on the hard drive. So I am getting a bit tired of the 'spinning beach ball' every few seconds. Deleting PLIST files, PRAM resets, file cleaning, memory cleaning, dicking around with WiFi channels and doing a f**king rain dance to the king of the Potato People. Hey Apple... SORT OUT SIERRA AND GET MY F***ING MAC FAST AGAIN!!!!!!!!!