I just recently downloaded the latest public release of Xcode (6.3) and I noticed the storyboard for my app is now low res on my Retina MacBook Pro. Images, text and standard UI elements all appear blurry. On the actual device everything looks fine and code still looks sharp its just while working in the Interface Builder.
Has anybody else noticed this and figured out a way to fix it? This is happening to me in both Swift and Objective-C projects including in Apple's sample projects (Master-Detail Application and etc).
I submitted this as a bug report, and Apple responded by saying that it is the desired appearance. They did not give an explanation, that was all they said.
It appears to be related to a bug in the newest iOS SDK, and as a workaround, they've forced Interface Builder to render everything at 1x. Currently, there doesn't seem to be any solution to this annoying problem other than to wait.
Just installed Xcode version 6.3.2 and this issue appears to have been fixed.
Have you tried re-installation of the same version? That helped once. Alternatively, can upgrade to newer version, too.
来源：https://stackoverflow.com/questions/29541449/interface-builder-appears-blurry-on-retina-display-in-xcode-6-3