diff --git a/CHANGES.txt b/CHANGES.txt
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,5 +1,8 @@
 Changelog for CmdArgs
 
+0.10.17
+    Add processValueIO for more controlled error messages
+    #529, don't include the stack trace in processValue
 0.10.16
     Minor improvement to error messages
 0.10.15
diff --git a/Data/Generics/Any.hs b/Data/Generics/Any.hs
--- a/Data/Generics/Any.hs
+++ b/Data/Generics/Any.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 {-# LANGUAGE ExistentialQuantification #-}
 
 module Data.Generics.Any where
diff --git a/System/Console/CmdArgs/Explicit.hs b/System/Console/CmdArgs/Explicit.hs
--- a/System/Console/CmdArgs/Explicit.hs
+++ b/System/Console/CmdArgs/Explicit.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE ScopedTypeVariables, CPP #-}
 {-|
     This module constructs command lines. You may either use the helper functions
     ('flagNone', 'flagOpt', 'mode' etc.) or construct the type directly. These
@@ -53,7 +53,7 @@
 -}
 module System.Console.CmdArgs.Explicit(
     -- * Running command lines
-    process, processArgs, processValue,
+    process, processArgs, processValue, processValueIO,
     -- * Constructing command lines
     module System.Console.CmdArgs.Explicit.Type,
     flagHelpSimple, flagHelpFormat, flagVersion, flagNumericVersion, flagsVerbosity,
@@ -112,7 +112,7 @@
             let var = mplus (lookup ("CMDARGS_HELPER_" ++ show (map toUpper $ head $ modeNames m ++ [nam])) env)
                             (lookup "CMDARGS_HELPER" env)
             case var of
-                Nothing -> run =<< (if modeExpandAt m then expandArgsAt else return) =<< getArgs
+                Nothing -> processValueIO m =<< (if modeExpandAt m then expandArgsAt else return) =<< getArgs
                 Just cmd -> do
                     res <- execute cmd m []
                     case res of
@@ -120,11 +120,7 @@
                             hPutStrLn stderr $ "Error when running helper " ++ cmd
                             hPutStrLn stderr err
                             exitFailure               
-                        Right args -> run args
-    where
-        run args = case process m args of
-            Left x -> do hPutStrLn stderr x; exitFailure
-            Right x -> return x
+                        Right args -> processValueIO m args
 
 
 readMay :: Read a => String -> Maybe a
@@ -133,15 +129,28 @@
                 _ -> Nothing
 
 
--- | Process a list of flags (usually obtained from @'getArgs'@ and @'expandArgsAt'@) with a mode. Displays
---   an error and exits with failure if the command line fails to parse, or returns
+#if __GLASGOW_HASKELL__ < 800
+errorWithoutStackTrace :: String -> a
+errorWithoutStackTrace = error
+#endif
+
+-- | Process a list of flags (usually obtained from @'getArgs'@ and @'expandArgsAt'@) with a mode.
+--   Throws an error if the command line fails to parse, or returns
 --   the associated value. Implemeneted in terms of 'process'. This function
 --   does not take account of any environment variables that may be set
 --   (see 'processArgs').
+--
+--   If you are in 'IO' you will probably get a better user experience by calling 'processValueIO'.
 processValue :: Mode a -> [String] -> a
 processValue m xs = case process m xs of
-    Left x -> error x
+    Left x -> errorWithoutStackTrace x
     Right x -> x
+
+-- | Like 'processValue' but on failure prints to stderr and exits the program.
+processValueIO :: Mode a -> [String] -> IO a
+processValueIO m xs = case process m xs of
+    Left x -> do hPutStrLn stderr x; exitFailure
+    Right x -> return x
 
 
 -- | Create a help flag triggered by @-?@/@--help@.
diff --git a/System/Console/CmdArgs/Explicit/Type.hs b/System/Console/CmdArgs/Explicit/Type.hs
--- a/System/Console/CmdArgs/Explicit/Type.hs
+++ b/System/Console/CmdArgs/Explicit/Type.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE CPP #-}
 
 module System.Console.CmdArgs.Explicit.Type where
 
@@ -7,9 +6,8 @@
 import Data.Char
 import Data.List
 import Data.Maybe
-#if __GLASGOW_HASKELL__ < 709
 import Data.Monoid
-#endif
+import Prelude
 
 
 -- | A name, either the name of a flag (@--/foo/@) or the name of a mode.
diff --git a/cmdargs.cabal b/cmdargs.cabal
--- a/cmdargs.cabal
+++ b/cmdargs.cabal
@@ -1,7 +1,7 @@
 cabal-version:      >= 1.18
 build-type:         Simple
 name:               cmdargs
-version:            0.10.16
+version:            0.10.17
 license:            BSD3
 license-file:       LICENSE
 category:           Console