To make Photoshop CS6 behave like a non-retina application, select the Photoshop application in the Finder and choose File > Get Info. If you have a Retina display, under General, there will be an option to “Open in Low Resolution”. This probably isn’t something that most people will do, but I used it when demonstrating Photoshop last week.
You will only have Retina support if you have downloaded the update to Photoshop CS6. Here’s how to get the update:
1. In Photoshop, choose Help > Updates.
2. The Adobe Application Manager will launch. Select Adobe Photoshop CS6 and choose Update.
How to confirm that the Update worked
1. In Photoshop, choose Help > About Photoshop (Win), or Photoshop > About Photoshop (Mac)
2. For Mac perpetual customers, the version at the top should be Version: 13.0.3
3. For Win/Mac Creative Cloud members, the version at the top should be Version: 13.1.1

this is very helpful, few people asked me about it…now I know the answer! thanks!
I have followed your instructions on how to open cs6 in low resolution on my retina display. Under general info I do not have the option to “open in low res”. I am using CS6 13.0.4. What are my other options to do this or am I missing something?
I’m not sure why you don’t have that option Matt. Can you post the issue to either of these forums to see if other customers are experiencing the same problem and if so, if they have found a solution.
http://forums.adobe.com/community/lightroom
http://feedback.photoshop.com/photoshop_family