How to Install and Run Yosemite in Parallels? I'm not ready to commit to Yosemite yet as my primary OS.  So I thought I'd load up a Parallels VM to try it out.  

Although Parallels seems to create the Yosemite .dmg file correctly, it just won't finish loading.  I get messages about having to "download additional components" with tens if not hundreds of hours remaining.  If I let it run overnight, I wake up to a message that something failed.

So is it not possible to install Yosemite as a Parallels VM? (I'm running Parallels v10.1.0 on a 2014 MacBook Pro)  Has anyone successfully gotten this to work?
Yes - I've gotten installs of Yosemite to work on Parallels - but on a Mac Pro. I installed Yosemite fairly seamlessly from a Recovery HD - so you would want to install Yosemite onto an external drive (or SD media if your mac has one equipped) and then virtualize from the Recovery HD if you can't test well enough on a second install of OS X.