diff --git a/System/Random/MWC.hs b/System/Random/MWC.hs
--- a/System/Random/MWC.hs
+++ b/System/Random/MWC.hs
@@ -46,11 +46,11 @@
 
 import Control.Exception (IOException, catch)
 import Control.Monad (ap, liftM, unless)
-import Control.Monad.ST (ST)
 import Control.Monad.Primitive (PrimMonad, PrimState, unsafePrimToIO)
+import Control.Monad.ST (ST)
 import Data.Bits ((.&.), (.|.), xor)
-import Data.IORef (atomicModifyIORef, newIORef)
 import Data.Int (Int8, Int16, Int32, Int64)
+import Data.IORef (atomicModifyIORef, newIORef)
 import Data.Ratio ((%), numerator)
 import Data.Time.Clock.POSIX (getPOSIXTime)
 import Data.Typeable (Typeable)
@@ -61,11 +61,13 @@
 import GHC.Base (Int(I#))
 import GHC.Word (Word64(W64#), uncheckedShiftL64#, uncheckedShiftRL64#)
 import Prelude hiding (catch)
+import qualified Data.Vector.Generic as G
+import qualified Data.Vector.Generic.Mutable as GM
+import qualified Data.Vector.Unboxed as I
+import qualified Data.Vector.Unboxed.Mutable as M
 import System.CPUTime (cpuTimePrecision, getCPUTime)
 import System.IO (IOMode(..), hGetBuf, hPutStrLn, stderr, withBinaryFile)
 import System.IO.Unsafe (unsafePerformIO)
-import qualified Data.Vector.Unboxed as I
-import qualified Data.Vector.Unboxed.Mutable as M
 
 -- | The class of types for which we can generate uniformly
 -- distributed random variates.
@@ -258,9 +260,16 @@
 newtype Seed = Seed (I.Vector Word32)
     deriving (Eq, Show, Typeable)
 
+-- Safe version of unsafeFreeze.
+safeFreeze :: (PrimMonad m, Vector v a) => G.Mutable v (PrimState m) a -> m (v a)
+safeFreeze v = do
+  v' <- GM.unsafeNew (GM.length v)
+  GM.unsafeCopy v' v
+  unsafeFreeze v'
+
 -- | Save the state of a 'Gen', for later use by 'restore'.
 save :: PrimMonad m => Gen (PrimState m) -> m Seed
-save (Gen q) = Seed `liftM` unsafeFreeze q
+save (Gen q) = Seed `liftM` safeFreeze q
 {-# INLINE save #-}
 
 -- | Create a new 'Gen' that mirrors the state of a saved 'Seed'.
diff --git a/mwc-random.cabal b/mwc-random.cabal
--- a/mwc-random.cabal
+++ b/mwc-random.cabal
@@ -1,5 +1,5 @@
 name:           mwc-random
-version:        0.7.0.0
+version:        0.7.0.1
 synopsis:       Fast, high quality pseudo random number generation
 description:
   This package contains code for generating high quality random