diff --git a/Test.hs b/Test.hs
--- a/Test.hs
+++ b/Test.hs
@@ -29,7 +29,7 @@
 
 stdTestCase :: Int -> FilePath -> IO ()
 stdTestCase dataLen outputFile = do
-    testData <- replicateM dataLen $ randomRIO ('\0', '\255')
+    testData <- replicateM dataLen $ randomRIO ('\0', '\127')
     writeFile outputFile testData
     testData' <- readFile outputFile
     unless (testData == testData') . fail $ "stdTestCase: failed with " ++ show dataLen ++ " " ++ show outputFile
diff --git a/cautious-file.cabal b/cautious-file.cabal
--- a/cautious-file.cabal
+++ b/cautious-file.cabal
@@ -1,23 +1,23 @@
 name:                cautious-file
-version:             0.1.5
+version:             1.0.2
 Cabal-Version:	     >= 1.6
 synopsis:            Ways to write a file cautiously, to reduce the chances of problems such as data loss due to crashes or power failures
-description:         If the posix flag is enabled, posix-specific functions are used to reduce the chance of data loss further
+description:         On non-Windows systems, posix-specific functions are used to reduce the chance of data loss further
 category:            System
 license:             BSD3
 license-file:        LICENSE
-copyright:	     Copyright (C) Robin Green 2009
+copyright:	     Copyright (C) Robin Green 2009, 2011
 author:              Robin Green
 maintainer:          Robin Green <greenrd@greenrd.org>
 build-type:	     Custom
 stability:	     experimental
 bug-reports:	     mailto:greenrd@greenrd.org
-tested-with:	     GHC == 6.10.3
+tested-with:	     GHC == 7.0.2
 extra-source-files:      Test.hs
 
 source-repository head
   type:     darcs
-  location: http://patch-tag.com/publicrepos/cautious-file
+  location: http://patch-tag.com/r/greenrd/cautious-file
 
 Flag posix
     description: Use POSIX-specific features
@@ -25,8 +25,8 @@
 
 Library
   hs-source-dirs:       src
-  build-Depends:	base >= 4, base < 5, directory, filepath, bytestring
-  if flag(posix)
+  build-Depends:	base >= 4, base < 5, directory >= 1.1, directory < 1.3, filepath >= 1.2, filepath < 1.4, bytestring >= 0.9, bytestring < 0.11
+  if flag(posix) && !os(Windows)
     cpp-options: -D_POSIX
     build-Depends: unix
     exposed-modules:    System.Posix.ByteLevel, System.Posix.Fsync
diff --git a/src/System/IO/Cautious.hs b/src/System/IO/Cautious.hs
--- a/src/System/IO/Cautious.hs
+++ b/src/System/IO/Cautious.hs
@@ -13,14 +13,14 @@
 
 import Prelude hiding (writeFile)
 
+import Control.Exception (tryJust)
+import Control.Monad (guard)
 import Data.ByteString.Lazy.Char8 (ByteString, pack)
 import System.Directory (canonicalizePath, renameFile)
 import System.FilePath (splitFileName)
 import System.IO (openTempFile)
-#ifdef _POSIX
-import Control.Exception (tryJust)
-import Control.Monad (guard)
 import System.IO.Error (isDoesNotExistError)
+#ifdef _POSIX
 import System.Posix.ByteLevel (writeAllL)
 import System.Posix.Files (fileMode, getFileStatus, setFdMode)
 import System.Posix.Fsync (fsync)
@@ -41,16 +41,19 @@
 writeFileWithBackup :: IO () -> FilePath -> String -> IO ()
 writeFileWithBackup backup fp = writeFileWithBackupL backup fp . pack
 
+ignoreNotFound :: IO a -> IO (Either () a)
+ignoreNotFound = tryJust (guard . isDoesNotExistError)
+
 -- | Backs up the old version of the file with "backup". "backup" must not fail if there is no
 -- old version of the file.
 writeFileWithBackupL :: IO () -> FilePath -> ByteString -> IO ()
 writeFileWithBackupL backup fp bs = do
-    cfp <- canonicalizePath fp
+    cfp <- either (const fp) id `fmap` ignoreNotFound (canonicalizePath fp)
     (tempFP, handle) <- uncurry openTempFile $ splitFileName cfp
 #ifdef _POSIX
     fd <- handleToFd handle
     writeAllL fd bs
-    tryJust (\e -> guard (isDoesNotExistError e) >> return ()) $ setFdMode fd . fileMode =<< getFileStatus cfp
+    _ <- ignoreNotFound $ setFdMode fd . fileMode =<< getFileStatus cfp
     fsync fd
     closeFd fd
 #else
diff --git a/src/System/Posix/ByteLevel.hsc b/src/System/Posix/ByteLevel.hsc
--- a/src/System/Posix/ByteLevel.hsc
+++ b/src/System/Posix/ByteLevel.hsc
@@ -9,7 +9,7 @@
 import Data.Function (fix)
 import Foreign.C.Error (throwErrnoIfMinus1Retry)
 import Foreign.C.String (CString, CStringLen)
-import Foreign.C.Types (CInt, CSize)
+import Foreign.C.Types (CInt(..), CSize(..))
 import System.Posix.Types (ByteCount, Fd(..))
 
 #include <unistd.h>
diff --git a/src/System/Posix/Fsync.hsc b/src/System/Posix/Fsync.hsc
--- a/src/System/Posix/Fsync.hsc
+++ b/src/System/Posix/Fsync.hsc
@@ -2,7 +2,7 @@
 module System.Posix.Fsync (fsync) where
 
 import Foreign.C.Error (throwErrnoIfMinus1_)
-import Foreign.C.Types (CInt)
+import Foreign.C.Types (CInt(..))
 import System.Posix.Types (Fd(..))
 
 #include <unistd.h>