diff --git a/System/Unix/ProcessStrict.hs b/System/Unix/ProcessStrict.hs
--- a/System/Unix/ProcessStrict.hs
+++ b/System/Unix/ProcessStrict.hs
@@ -12,7 +12,7 @@
     ) where
     
 import Control.Exception hiding (catch)
-import Control.Parallel.Strategies (rnf)
+import Control.Parallel.Strategies (rdeepseq)
 import System.Process (waitForProcess, runInteractiveProcess, runInteractiveCommand)
 import System.IO (hSetBinaryMode, hClose, hGetContents)
 import System.Unix.Process
@@ -39,8 +39,8 @@
        hClose inp
        outStr <- hGetContents out
        errStr <- hGetContents err
-       evaluate (rnf outStr) -- read output strictly
-       evaluate (rnf errStr) -- read stderr strictly
+       _ <- evaluate (rdeepseq outStr) -- read output strictly
+       _ <- evaluate (rdeepseq errStr) -- read stderr strictly
        ec <- waitForProcess pid
        return (outStr, errStr, ec)
 
@@ -64,8 +64,8 @@
        hClose inp
        outStr <- hGetContents out
        errStr <- hGetContents err
-       evaluate (rnf outStr) -- read output strictly
-       evaluate (rnf errStr) -- read stderr strictly
+       _ <- evaluate (rdeepseq outStr) -- read output strictly
+       _ <- evaluate (rdeepseq errStr) -- read stderr strictly
        ec <- waitForProcess pid
        return (outStr, errStr, ec)
 
diff --git a/Unixutils.cabal b/Unixutils.cabal
--- a/Unixutils.cabal
+++ b/Unixutils.cabal
@@ -1,11 +1,11 @@
 Name:           Unixutils
-Version:        1.35
+Version:        1.36
 License:        BSD3
 License-File:	COPYING
 Author:         Jeremy Shaw, David Fox
 Homepage:       http://src.seereason.com/haskell-unixutils
 Category:	System
-Build-Depends:  array, base >= 4 && <5, containers, mtl, HUnit, unix, regex-tdfa, process < 3, bytestring, directory, time, old-time, parallel, filepath
+Build-Depends:  array, base >= 4 && <5, containers, mtl, HUnit, unix, regex-tdfa, process < 3, bytestring, directory, time, old-time, parallel >= 2, filepath
 Synopsis:       A crude interface between Haskell and Unix-like operating systems
 Maintainer:     jeremy@n-heptane.com
 Description: