

I will also keep the iMovie content on the external HD. I keep all my iTunes music and iPhotos pictures & videos on an external drive, so there is ample room on the internal HD. The info for my MacBook Pro from "About this Mac": I would like to get iMovie (Version 10), which I believe has the linear timeline I prefer, but requires OS Version 11 (El Capitan). I currently have iMovie Version 8, which came w/ my laptop's original OS, and I find difficult to work with b/c of the wrapping timeline in the upper left part of the screen - as opposed to an expanding/contracting linear timeline on the bottom of the screen (as with AVID and Adobe Premiere).

The main reason I want to upgrade the OS is to get a better version of iMovie. My laptop is older and kinda slow, but works fine with Yosemite. Is there any reason NOT to upgrade a mid-2009 MacBook Pro from Yosemite (OS Version 10.10) to El Capitan (OS Version 10.11)? My understanding is that latest OS I can upgrade to is El Capitan my MacBook Pro will not upgrade to Sienna (OS Version 10.12).
