What's the difference between "Clean Up By" & "Sort By"? Both have the same options. It seems to me that "Sort By" is automatic & remains the way it is set even if the computer is turned off. Is that correct? I have a mini & a laptop. Both had Mavericks. Both were locking up & frequently showing the spinning beach ball. I was tired of force quitting an app so I nuked the hard drive on each one & did a clean install of Yosemite on each one. Anyway, before the nuke, I noticed that a flash drive icon would appear under the hard drive icon. Now, after a clean install of Yosemite, when I plug in a flash drive, the icon appears as the very last icon. I chose Sort By > Name & the next time that I plugged in a flash drive, the flash drive appeared below the hard drive. That's the way that I want it. So, is my assumption correct? Sort By is "permanent" & Clean Up By is used to rearrange the icons?