diff --git a/bin/brew b/bin/brew
index a961c9bdaa..716916c76b 100755
--- a/bin/brew
+++ b/bin/brew
@@ -198,7 +198,7 @@ begin
       abort "Sorry, Homebrew does not support your computer's CPU architecture."
     end
 
-    raise "Cannot write to #{HOMEBREW_CELLAR}" unless HOMEBREW_CELLAR.writable?
+    raise "Cannot write to #{HOMEBREW_CELLAR}" if HOMEBREW_CELLAR.exist? and not HOMEBREW_CELLAR.writable?
     raise "Cannot write to #{HOMEBREW_PREFIX}" unless HOMEBREW_PREFIX.writable?
 
     ################################################################# warnings