Display resolution 1024x768, Mavericks in PDT 10 under Yosemite

Yosemite killed one of my favorite apps so I installed Mavericks under Parallels 10.

On a 27" iMac with 2560x1440 pixels, in full screen Mavericks is letterboxed and displays 1024x768 pixels. Mavericks System Preferences =>Displays offers no other resolution. The auxiliary monitor is ignored.

I don't mind too much being restricted to one monitor, but I need full resolution on the main, since what I want to do in this VM is edit HD video.

I assume I must have clicked the wrong thing during installation. Is there any way to correct this, or, if I have to reinstall, what must I do correctly this time?

 

Hello JohnV1,

Re-installation of Virtual Machine is not required.
This should help you with the screen resolution issue : http://kb.parallels.com/114700

 

Thanks for trying, but the referenced page seems to apply only to portable Macs with Retina displays and Windows guests. I am hosting Mavericks under Yosemite on an iMac 27". I think what I need to do is back the guest all the way down to 10.6.8.