diff --git a/System/Console/CmdArgs/Explicit/Process.hs b/System/Console/CmdArgs/Explicit/Process.hs
--- a/System/Console/CmdArgs/Explicit/Process.hs
+++ b/System/Console/CmdArgs/Explicit/Process.hs
@@ -7,6 +7,7 @@
 import Data.Maybe
 import System.Environment
 import System.Exit
+import System.IO
 
 
 -- | Process the flags obtained by @getArgs@ with a mode. Displays
@@ -16,7 +17,7 @@
 processArgs m = do
     xs <- getArgs
     case process m xs of
-        Left x -> do putStrLn x; exitFailure
+        Left x -> do hPutStrLn stderr x; exitFailure
         Right x -> return x
 
 
diff --git a/System/Console/CmdArgs/Implicit/Read.hs b/System/Console/CmdArgs/Implicit/Read.hs
--- a/System/Console/CmdArgs/Implicit/Read.hs
+++ b/System/Console/CmdArgs/Implicit/Read.hs
@@ -1,4 +1,4 @@
-
+{-# LANGUAGE PatternGuards #-}
 module System.Console.CmdArgs.Implicit.Read(isReadBool, toReadContainer, reader, addContainer, readHelp) where
 
 import Data.Generics.Any
@@ -93,6 +93,7 @@
 
 readEnum:: String -> [(String,a)] -> Either String a
 readEnum a xs | null ys = Left $ "Could not read, expected one of: " ++ unwords (map fst xs)
+              | Just (_,el) <- find (\x -> a == fst x) ys = Right el
               | length ys > 1 = Left $ "Ambiguous read, could be any of: " ++ unwords (map fst ys)
               | otherwise = Right $ snd $ head ys
     where ys = filter (\x -> a `isPrefixOf` fst x) xs
diff --git a/cmdargs.cabal b/cmdargs.cabal
--- a/cmdargs.cabal
+++ b/cmdargs.cabal
@@ -1,7 +1,7 @@
 cabal-version:      >= 1.6
 build-type:         Simple
 name:               cmdargs
-version:            0.6.4
+version:            0.6.5
 license:            BSD3
 license-file:       LICENSE
 category:           Console