On Migration and old junk files: I have been migrating this OS since OS 9 so more than 15 years of built up old apps and non used system related files are lurking on the drive. Since I'm moving only ≈ 225 GB's from the iMac to the new 512 SSD, space and slow down from this old garbage I'm guessing is a non issue, but it would 'feel good' to discard some of it. I just have no idea what I would look for to delete system info or old app wise to do a clean installation. To add to it, my old 2006 iMac came used with LOTS of software on it that is now useless (w/ Lion like Photoshop) and more (that I am not even aware of ;o) that will become useless with any of the higher OS's. I am off to read 'Teh Google' on this, but any pointers or links appreciated. Which OS to start 2012 Mini 2.6, 16 GB, 512SSD with??? Having just upgraded my old iMac late 2006 from 10.6.8 Snow Lep. to 10.7.5 Lion I have ZERO experience w/ 10.9, 10.10 or 10.11. I have read that El Capitan cleaned up some slowness or bugs from Yosemite and that Mavericks had it's issues. That 10.11.1 had problems w/ MS Office, but hopefully that got fixed by the current 10.11.x. The main two apps I need compatibility with are Quicken for Mac 2007 and MS Office (version unsure). The empty 2012 Mini now has 10.9.5 Mav. The iMac I'll migrate data from is hardware maxed at 10.7.5. 1) What OS do you recommend going with on new to me 2012 Mini. 2) Would I put the Mini at the desired OS before the migration from the old iMac? 3) Or do I migrate from iMac Lion to Mini Mavericks, then upgrade the Mini to the desired OS? Any hints or tips welcomed. On Hard drives, I decided I want to unfuse the 512 SSD from the 1TB HDD. So I'll read up on one of the helpful links already supplied (thank you) on how to proceed with that.