So my old iMac died and I found a pretty good deal on an open box 2013 iMac from Best Buy. It seems to be running pretty smoothly, but I do have a few concerns: - There is no startup chime - The mouse seems to be a little "sticky" (this could just be me getting used to the Magic Mouse vs. a standard USB mouse) - Ineligible for AppleCare None of these are huge problems (the lack of a chime is honestly the most interesting to me — is this cause for concern?), but I could get a "new in-box" 2013 iMac for just a little more, and it would be eligible for AppleCare. On a related note, I specifically went for a 2013 model, hoping I would be able to install Yosemite or El Capitan, but I've tried to restore to factory settings, and the only option is to install Sierra. Is there a way around this? My dead iMac is a 2012 model, so I have several older versions of OS X available to my Apple ID. Thank you!!!