diff --git a/Library/Homebrew/dev-cmd/extract.rb b/Library/Homebrew/dev-cmd/extract.rb
index c6d1682521b17..bae5e4cb90dab 100644
--- a/Library/Homebrew/dev-cmd/extract.rb
+++ b/Library/Homebrew/dev-cmd/extract.rb
@@ -202,7 +202,7 @@ def extract
     # Remove bottle blocks, they won't work.
     result.sub!(/  bottle do.+?end\n\n/m, "") if destination_tap != source_tap
 
-    path = destination_tap.path/"Formula/#{name}@#{version}.rb"
+    path = destination_tap.path/"Formula/#{name}@#{version.to_s.downcase}.rb"
     if path.exist?
       unless args.force?
         odie <<~EOS