diff --git a/UnexceptionalIO/Trans.hs b/UnexceptionalIO/Trans.hs
--- a/UnexceptionalIO/Trans.hs
+++ b/UnexceptionalIO/Trans.hs
@@ -80,7 +80,7 @@
 runExceptIO = liftIO . UIO.runEitherIO . Trans.runExceptT
 
 #if MIN_VERSION_transformers(0,5,3)
-instance (UIO.Unexceptional m) => UIO.Unexceptional (Trans.AccumT w m) where
+instance (UIO.Unexceptional m, Monoid w) => UIO.Unexceptional (Trans.AccumT w m) where
 	lift = Trans.lift . UIO.lift
 #endif
 
diff --git a/unexceptionalio-trans.cabal b/unexceptionalio-trans.cabal
--- a/unexceptionalio-trans.cabal
+++ b/unexceptionalio-trans.cabal
@@ -1,5 +1,5 @@
 name:            unexceptionalio-trans
-version:         0.5.0
+version:         0.5.1
 cabal-version:   >=1.8
 license:         OtherLicense
 license-file:    COPYING
@@ -30,7 +30,7 @@
         build-depends:
                 base == 4.*,
                 transformers,
-                unexceptionalio == 0.4.0
+                unexceptionalio == 0.5.0
 
 source-repository head
         type:     git