diff --git a/ats-setup.cabal b/ats-setup.cabal
--- a/ats-setup.cabal
+++ b/ats-setup.cabal
@@ -1,5 +1,5 @@
 name:                ats-setup
-version:             0.1.0.1
+version:             0.1.0.2
 synopsis:            ATS scripts for Cabal builds
 description:         This package contains various scripts that go in a package's @Setup.hs@ to make building libraries with ATS dependencies easier.
 license:             BSD3
diff --git a/src/Distribution/ATS.hs b/src/Distribution/ATS.hs
--- a/src/Distribution/ATS.hs
+++ b/src/Distribution/ATS.hs
@@ -73,7 +73,7 @@
 fetchDependency :: ATSDependency -> IO ()
 fetchDependency (ATSDependency libNameATS dirName url) = do
 
-    needsSetup <- not <$> doesDirectoryExist dirName
+    needsSetup <- not <$> doesDirectoryExist (dirName ++ "/unpacked")
 
     when needsSetup $ do
 
@@ -87,6 +87,7 @@
         Tar.unpack dirName . Tar.read . decompress $ response
 
         doing "Setting up"
+        writeFile (dirName ++ "/unpacked") ""
         needsMove <- doesDirectoryExist (dirName ++ "/package")
         when needsMove $ do
             renameDirectory (dirName ++ "/package") "tempdir"