diff --git a/Casks/rstudio-preview.rb b/Casks/rstudio-preview.rb
index 4325056ed..c4d7b5fb3 100644
--- a/Casks/rstudio-preview.rb
+++ b/Casks/rstudio-preview.rb
@@ -2,7 +2,7 @@ cask :v1 => 'rstudio-preview' do
   version :latest
   sha256 :no_check
 
-  url "http://www.rstudio.org/download/latest/preview/desktop/mac/RStudio-latest.dmg"
+  url 'http://www.rstudio.org/download/latest/preview/desktop/mac/RStudio-latest.dmg'
   homepage 'http://www.rstudio.com/ide/download/preview'
   license :unknown