diff --git a/src/Test/Framework/Providers/Sandbox.hs b/src/Test/Framework/Providers/Sandbox.hs
--- a/src/Test/Framework/Providers/Sandbox.hs
+++ b/src/Test/Framework/Providers/Sandbox.hs
@@ -97,9 +97,9 @@
         exitHandler = throw
         interruptHandler :: AsyncException -> Sandbox a
         interruptHandler UserInterrupt = liftIO exitFailure
-        interruptHandler e = Sandbox . throwError $ show e
+        interruptHandler e = throwError $ show e
         otherHandler :: SomeException -> Sandbox a
-        otherHandler = Sandbox . throwError . show
+        otherHandler = throwError . show
 
 -- | Displays a progress update during a test.
 yieldProgress :: String     -- ^ Text to display
diff --git a/test-framework-sandbox.cabal b/test-framework-sandbox.cabal
--- a/test-framework-sandbox.cabal
+++ b/test-framework-sandbox.cabal
@@ -1,5 +1,5 @@
 Name:           test-framework-sandbox
-Version:        0.1.0
+Version:        0.1.1
 Cabal-Version:  >= 1.14
 Category:       Testing
 Synopsis:       test-sandbox support for the test-framework package
@@ -29,14 +29,14 @@
 Source-Repository this
     Type:       git
     Location:   https://github.com/gree/haskell-test-sandbox
-    Tag:        test-framework-sandbox_0.1.0
+    Tag:        test-framework-sandbox_0.1.1
 
 Library
     Exposed-modules:    Test.Framework.Providers.Sandbox
                         Test.Framework.Providers.Sandbox.Internals
 
     Build-Depends:      base >=4 && <5, ansi-terminal, lifted-base, mtl,
-                        temporary, test-framework >=0.8.0.3, test-sandbox == 0.1.*,
+                        temporary, test-framework >=0.8.0.3, test-sandbox >= 0.1.7,
                         transformers
 
     Hs-source-dirs:     src
@@ -52,6 +52,6 @@
                  , HUnit
                  , test-framework >= 0.8.0.3
                  , test-framework-sandbox == 0.1.*
-                 , test-sandbox == 0.1.*
+                 , test-sandbox >= 0.1.7
                  , test-sandbox-hunit == 0.1.*
   Main-Is:         test/test.hs
diff --git a/test/test.hs b/test/test.hs
--- a/test/test.hs
+++ b/test/test.hs
@@ -1,4 +1,4 @@
-import Test.Framework.Providers.Sandbox (sandboxTests, sandboxTest, sandboxTestGroup, yieldProgress, withRetry)
+import Test.Framework.Providers.Sandbox (sandboxTests, sandboxTest, sandboxTestGroup, withRetry)
 import Test.Sandbox
 import Test.Framework
 import Test.Sandbox.HUnit (assertEqual)
@@ -13,12 +13,12 @@
   sandboxTest "retry" $ do
     val <- liftIO $ newIORef 0
     withRetry 10 $ do
-      val' <- liftIO $ readIORef val
+      val' <- liftIO $ readIORef val :: Sandbox Integer
       liftIO $ writeIORef val (val'+1)
       assertEqual "retry 10(single)" 9 val'
     withRetry 2 $ do
       withRetry 3 $ do
-        val' <- liftIO $ readIORef val
+        val' <- liftIO $ readIORef val :: Sandbox Integer
         liftIO $ writeIORef val (val'+1)
         assertEqual "retry 6(double loop)" 15 val'
   ]
@@ -31,11 +31,11 @@
   withRetry 10 $
     sandboxTestGroup "retryTest(outside of testGroup)" [
       sandboxTest "retry" $ do
-        val' <- liftIO $ readIORef val
+        val' <- liftIO $ readIORef val :: Sandbox Integer
         liftIO $ writeIORef val (val'+1)
         assertEqual "retry 10(single)" 9 val'
     , sandboxTest "retry2" $ do
-        val2' <- liftIO $ readIORef val2
+        val2' <- liftIO $ readIORef val2 :: Sandbox Integer
         liftIO $ writeIORef val2 (val2'+1)
         assertEqual "retry 10(single)" 9 val2'
     ]