diff --git a/lib/taskana-core/src/test/java/acceptance/AbstractAccTest.java b/lib/taskana-core/src/test/java/acceptance/AbstractAccTest.java
index 39d89af73..6048ce30f 100644
--- a/lib/taskana-core/src/test/java/acceptance/AbstractAccTest.java
+++ b/lib/taskana-core/src/test/java/acceptance/AbstractAccTest.java
@@ -1,6 +1,5 @@
 package acceptance;
 
-import java.io.IOException;
 import java.sql.SQLException;
 import java.time.Instant;
 import java.time.LocalDate;
@@ -37,7 +36,7 @@ public abstract class AbstractAccTest {
         resetDb(false);
     }
 
-    public static void resetDb(boolean dropTables) throws SQLException, IOException {
+    public static void resetDb(boolean dropTables) throws SQLException {
         DataSource dataSource = TaskanaEngineTestConfiguration.getDataSource();
         String schemaName = TaskanaEngineTestConfiguration.getSchemaName();
         SampleDataGenerator sampleDataGenerator = new SampleDataGenerator(dataSource, schemaName);
diff --git a/lib/taskana-core/src/test/java/acceptance/jobs/TaskCleanupJobAccTest.java b/lib/taskana-core/src/test/java/acceptance/jobs/TaskCleanupJobAccTest.java
index 1e49f54cf..b341ab062 100644
--- a/lib/taskana-core/src/test/java/acceptance/jobs/TaskCleanupJobAccTest.java
+++ b/lib/taskana-core/src/test/java/acceptance/jobs/TaskCleanupJobAccTest.java
@@ -3,6 +3,7 @@ package acceptance.jobs;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 
+import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -35,15 +36,21 @@ class TaskCleanupJobAccTest extends AbstractAccTest {
     TaskService taskService;
 
     @BeforeEach
-    void before() {
+    void before() throws SQLException {
+        //required if single tests modify database
+        //TODO split test class into readOnly & modifying tests to improve performance
+        resetDb(false);
+        resetDb(false);
         taskService = taskanaEngine.getTaskService();
     }
 
     @WithAccessId(userName = "admin")
     @Test
     void shouldCleanCompletedTasksUntilDate() throws Exception {
+
+        createAndCompleteTask();
         long totalTasksCount = taskService.createTaskQuery().count();
-        assertEquals(73, totalTasksCount);
+        assertEquals(74, totalTasksCount);
 
         taskanaEngine.getConfiguration().setTaskCleanupJobAllCompletedSameParentBusiness(false);
 
@@ -51,14 +58,14 @@ class TaskCleanupJobAccTest extends AbstractAccTest {
         job.run();
 
         totalTasksCount = taskService.createTaskQuery().count();
-        assertEquals(67, totalTasksCount);
+        assertEquals(68, totalTasksCount);
     }
 
     @WithAccessId(userName = "admin")
     @Test
     void shouldCleanCompletedTasksUntilDateWithSameParentBussiness() throws Exception {
         long totalTasksCount = taskService.createTaskQuery().count();
-        assertEquals(68, totalTasksCount);
+        assertEquals(73, totalTasksCount);
 
         taskanaEngine.getConfiguration().setTaskCleanupJobAllCompletedSameParentBusiness(true);
 
@@ -77,7 +84,7 @@ class TaskCleanupJobAccTest extends AbstractAccTest {
         job.run();
 
         totalTasksCount = taskService.createTaskQuery().count();
-        assertEquals(67, totalTasksCount);
+        assertEquals(66, totalTasksCount);
     }
 
     @WithAccessId(userName = "admin")
diff --git a/lib/taskana-core/src/test/java/acceptance/task/QueryTasksAccTest.java b/lib/taskana-core/src/test/java/acceptance/task/QueryTasksAccTest.java
index 2b84c288b..05afe8dde 100644
--- a/lib/taskana-core/src/test/java/acceptance/task/QueryTasksAccTest.java
+++ b/lib/taskana-core/src/test/java/acceptance/task/QueryTasksAccTest.java
@@ -15,6 +15,7 @@ import static pro.taskana.TaskQueryColumnName.CLASSIFICATION_KEY;
 import static pro.taskana.TaskQueryColumnName.OWNER;
 import static pro.taskana.TaskQueryColumnName.STATE;
 
+import java.sql.SQLException;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
@@ -22,6 +23,7 @@ import java.util.Map;
 import org.apache.ibatis.session.Configuration;
 import org.apache.ibatis.session.SqlSession;
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 
@@ -53,6 +55,13 @@ import pro.taskana.security.WithAccessId;
 @ExtendWith(JAASExtension.class)
 class QueryTasksAccTest extends AbstractAccTest {
 
+    @BeforeEach
+    void before() throws SQLException {
+        //required if single tests modify database
+        //TODO split test class into readOnly & modifying tests to improve performance
+        resetDb(false);
+    }
+
     @WithAccessId(
         userName = "teamlead_1",
         groupNames = {"admin"})
@@ -112,7 +121,7 @@ class QueryTasksAccTest extends AbstractAccTest {
             .orderByClassificationKey(DESCENDING)
             .listValues(CLASSIFICATION_KEY, null);
         assertNotNull(columnValueList);
-        assertEquals(7, columnValueList.size());
+        assertEquals(6, columnValueList.size());
     }
 
     @WithAccessId(
@@ -896,7 +905,7 @@ class QueryTasksAccTest extends AbstractAccTest {
         List<TaskSummary> results = taskService.createTaskQuery()
             .classificationCategoryIn("MANUAL", "AUTOMATIC")
             .list();
-        assertEquals(4, results.size());
+        assertEquals(3, results.size());
     }
 
     @WithAccessId(
@@ -1085,7 +1094,7 @@ class QueryTasksAccTest extends AbstractAccTest {
         List<TaskSummary> results = taskService.createTaskQuery()
             .orderByCreator(DESCENDING)
             .list();
-        assertEquals("user_1_1", results.get(0).getCreator());
+        assertEquals("erstellerSpezial", results.get(0).getCreator());
     }
 
     @WithAccessId(