diff --git a/lib/XMonad/Internal/Shell.hs b/lib/XMonad/Internal/Shell.hs
index d44249f..70a3e6c 100644
--- a/lib/XMonad/Internal/Shell.hs
+++ b/lib/XMonad/Internal/Shell.hs
@@ -60,11 +60,11 @@ import qualified XMonad.Util.Run as XR
 -- In contrast with high-level APIs like 'System.Process', this will leave no
 -- trailing data structures to clean up, at the cost of being gross to look at
 -- and possibly more error-prone.
-runProcess :: P.ProcessConfig a b c -> IO ExitCode
+runProcess :: MonadUnliftIO m => P.ProcessConfig a b c -> m ExitCode
 runProcess = withDefaultSignalHandlers . P.runProcess
 
 -- | Run an action without xmonad's signal handlers.
-withDefaultSignalHandlers :: IO a -> IO a
+withDefaultSignalHandlers :: MonadUnliftIO m => m a -> m a
 withDefaultSignalHandlers =
   bracket_ X.uninstallSignalHandlers X.installSignalHandlers