diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+zip-archive 0.4.2.1
+
+  * Fix Windows build regression (#61).
+
 zip-archive 0.4.2
 
   * Fix problem with files with colon (#89).
diff --git a/src/Codec/Archive/Zip.hs b/src/Codec/Archive/Zip.hs
--- a/src/Codec/Archive/Zip.hs
+++ b/src/Codec/Archive/Zip.hs
@@ -91,7 +91,9 @@
 import qualified Data.Digest.CRC32 as CRC32
 import qualified Data.Map as M
 import Control.Applicative
-#ifndef _WINDOWS
+#ifdef _WINDOWS
+import Data.Char (isLetter)
+#else
 import System.Posix.Files ( setFileTimes, setFileMode, fileMode, getSymbolicLinkStatus, symbolicLinkMode, readSymbolicLink, isSymbolicLink, unionFileModes, createSymbolicLink, removeLink )
 import System.Posix.Types ( CMode(..) )
 import Data.List (partition)
diff --git a/zip-archive.cabal b/zip-archive.cabal
--- a/zip-archive.cabal
+++ b/zip-archive.cabal
@@ -1,5 +1,5 @@
 Name:                zip-archive
-Version:             0.4.2
+Version:             0.4.2.1
 Cabal-Version:       2.0
 Build-type:          Simple
 Synopsis:            Library for creating and modifying zip archives.