diff --git a/app/qute-symex/Main.hs b/app/qute-symex/Main.hs
--- a/app/qute-symex/Main.hs
+++ b/app/qute-symex/Main.hs
@@ -24,6 +24,7 @@
   )
 import Language.QBE.Types qualified as QBE
 import Options.Applicative qualified as OPT
+import SimpleBV qualified as SMT
 import System.Directory (createDirectoryIfMissing)
 import System.Exit (die)
 import System.FilePath (addExtension, (</>))
@@ -187,12 +188,14 @@
   case optLog opts of
     Just fn -> withFile fn WriteMode (exploreWithHandle ktest env func)
     Nothing -> do
-      engine <- newEngine env <$> defSolver
-      exploreEntry opts ktest engine func
+      solver <- defSolver
+      let engine = newEngine env solver
+      exploreEntry opts ktest engine func <* SMT.stop solver
   where
     exploreWithHandle ktest env func handle = do
-      engine <- newEngine env <$> logSolver handle
-      exploreEntry opts ktest engine func
+      solver <- logSolver handle
+      let engine = newEngine env solver
+      exploreEntry opts ktest engine func <* SMT.stop solver
 
 ------------------------------------------------------------------------
 
diff --git a/qute-cli.cabal b/qute-cli.cabal
--- a/qute-cli.cabal
+++ b/qute-cli.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.4
 name:               qute-cli
-version:            0.1.0
+version:            0.1.1
 synopsis:           Command-line interface for the Qute software analysis framework.
 description:
   This package provides a command-line interface for the software analysis framework
@@ -31,6 +31,10 @@
 common opts
     ghc-options: -fspecialise-aggressively
 
+common opts-symex
+    -- -threaded required by simple-smt, see <https://github.com/yav/simple-smt/issues/28>.
+    ghc-options: -threaded -rtsopts "-with-rtsopts=-N1"
+
 library
     import:           warnings, opts
     hs-source-dirs:   src
@@ -63,7 +67,7 @@
       optparse-applicative
 
 executable qute-symex
-    import:               warnings, opts
+    import:               warnings, opts, opts-symex
     main-is:              Main.hs
     hs-source-dirs:       app/qute-symex
     default-language:     GHC2021