diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index b38a47899a..b77121a194 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -16,7 +16,7 @@ module Homebrew extend self
         msg = blacklisted? name
         raise "No available formula for #{name}\n#{msg}" if msg
       end
-      if name =~ HOMEBREW_TAP_REGEX then
+      if not File.exist? name and name =~ HOMEBREW_TAP_REGEX then
         require 'cmd/tap'
         install_tap $1, $2
       end