diff --git a/Library/Homebrew/extend/os/mac/search.rb b/Library/Homebrew/extend/os/mac/search.rb
index 0b2c070acb..b937f64db4 100644
--- a/Library/Homebrew/extend/os/mac/search.rb
+++ b/Library/Homebrew/extend/os/mac/search.rb
@@ -34,7 +34,8 @@ module Homebrew
         results = cask_tokens.extend(Searchable)
                              .search(string_or_regex)
 
-        results |= DidYouMean::SpellChecker.new(dictionary: cask_tokens)
+        cask_names = Cask::Cask.all.map(&:full_name)
+        results += DidYouMean::SpellChecker.new(dictionary: cask_names)
                                            .correct(string_or_regex)
 
         results.sort.map do |name|
@@ -44,7 +45,7 @@ module Homebrew
           else
             cask.full_name
           end
-        end
+        end.uniq
       end
     end