diff --git a/.gitignore b/.gitignore
index 87a538f5ef..22b50914a2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,6 +13,7 @@
 # virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
 hs_err_pid*
 
+*.DS_Store
 /.idea/
 .idea/
 *.iml
@@ -168,7 +169,6 @@ Migrations/
 /target/
 /wfc/target/
 
-*.DS_Store
 /e2e-tests/emb-json/target/
 /process_data/
 /e2e-tests/spring-rest-multidb/target/
diff --git a/core/src/main/kotlin/org/evomaster/core/solver/SMTLibZ3DbConstraintSolver.kt b/core/src/main/kotlin/org/evomaster/core/solver/SMTLibZ3DbConstraintSolver.kt
index be3002deb8..8e0e5655e4 100644
--- a/core/src/main/kotlin/org/evomaster/core/solver/SMTLibZ3DbConstraintSolver.kt
+++ b/core/src/main/kotlin/org/evomaster/core/solver/SMTLibZ3DbConstraintSolver.kt
@@ -33,6 +33,7 @@ import java.nio.file.Files
 import java.nio.file.Paths
 import java.util.*
 import javax.annotation.PostConstruct
+import javax.annotation.PreDestroy
 
 /**
  * An SMT solver implementation using Z3 in a Docker container.
@@ -42,15 +43,12 @@ import javax.annotation.PostConstruct
  */
 class SMTLibZ3DbConstraintSolver() : DbConstraintSolver {
     private val resourcesFolder = System.getProperty("user.dir") + "/target/tmp"
-    private  lateinit var executor: Z3DockerExecutor
+    private lateinit var executor: Z3DockerExecutor
     private var idCounter: Long = 0L
 
     @Inject
     private lateinit var config: EMConfig
 
-    @Inject
-    private lateinit var time: SearchTimeController
-
     @PostConstruct
     private fun postConstruct() {
         if (config.generateSqlDataWithDSE) {
@@ -65,6 +63,7 @@ class SMTLibZ3DbConstraintSolver() : DbConstraintSolver {
     /**
      * Closes the Z3 Docker executor and cleans up temporary files.
      */
+    @PreDestroy
     override fun close() {
         executor.close()
         try {
diff --git a/solver/src/main/java/org/evomaster/solver/Z3DockerExecutor.java b/solver/src/main/java/org/evomaster/solver/Z3DockerExecutor.java
index 15dc50ecc8..ba91eb421f 100644
--- a/solver/src/main/java/org/evomaster/solver/Z3DockerExecutor.java
+++ b/solver/src/main/java/org/evomaster/solver/Z3DockerExecutor.java
@@ -84,6 +84,8 @@ public Optional<Map<String, SMTLibValue>> solveFromFile(String fileName) {
      */
     @Override
     public void close() {
-        z3Prover.stop();
+        if (z3Prover != null) {
+            z3Prover.stop();
+        }
     }
 }