diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index f39ebbd2a8..f7087ad8be 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -77,7 +77,7 @@ module Homebrew
           msg = "#{f.full_name}-#{f.installed_version} already installed"
           msg << ", it's just not linked" unless f.linked_keg.symlink? || f.keg_only?
           opoo msg
-        elsif f.oldname && (dir = HOMEBREW_CELLAR/f.oldname).exist? && !dir.subdirs.empty? \
+        elsif f.oldname && (dir = HOMEBREW_CELLAR/f.oldname).directory? && !dir.subdirs.empty? \
             && f.tap == Tab.for_keg(dir.subdirs.first).tap && !ARGV.force?
           # Check if the formula we try to install is the same as installed
           # but not migrated one. If --force passed then install anyway.
diff --git a/Library/Homebrew/cmd/outdated.rb b/Library/Homebrew/cmd/outdated.rb
index d432c4e839..7a199fcae2 100644
--- a/Library/Homebrew/cmd/outdated.rb
+++ b/Library/Homebrew/cmd/outdated.rb
@@ -18,10 +18,9 @@ module Homebrew
       all_versions = []
       older_or_same_tap_versions = []
 
-      if f.oldname && !f.rack.exist? && (dir = HOMEBREW_CELLAR/f.oldname).exist?
-        if f.tap == Tab.for_keg(dir.subdirs.first).tap
-          raise Migrator::MigrationNeededError.new(f)
-        end
+      if f.oldname && !f.rack.exist? && (dir = HOMEBREW_CELLAR/f.oldname).directory? &&
+        !dir.subdirs.empty? && f.tap == Tab.for_keg(dir.subdirs.first).tap
+        raise Migrator::MigrationNeededError.new(f)
       end
 
       f.rack.subdirs.each do |keg_dir|