diff --git a/src/main/java/li/strolch/agent/impl/CachedAuditTrail.java b/src/main/java/li/strolch/agent/impl/CachedAuditTrail.java
index 8449480a7..2469d1960 100644
--- a/src/main/java/li/strolch/agent/impl/CachedAuditTrail.java
+++ b/src/main/java/li/strolch/agent/impl/CachedAuditTrail.java
@@ -56,7 +56,8 @@ public class CachedAuditTrail implements AuditTrail {
 	}
 
 	@Override
-	public boolean hasAudit(StrolchTransaction tx, String type, Long id) {
+	public synchronized boolean hasAudit(StrolchTransaction tx, String type, Long id) {
+
 		return this.auditMap.containsElement(type, id);
 	}
 
@@ -73,7 +74,7 @@ public class CachedAuditTrail implements AuditTrail {
 	}
 
 	@Override
-	public long querySize(StrolchTransaction tx, String type, DateRange dateRange) {
+	public synchronized long querySize(StrolchTransaction tx, String type, DateRange dateRange) {
 		long size = 0;
 
 		Map<Long, Audit> byType = this.auditMap.getMap(type);
@@ -89,17 +90,17 @@ public class CachedAuditTrail implements AuditTrail {
 	}
 
 	@Override
-	public Set<String> getTypes(StrolchTransaction tx) {
+	public synchronized Set<String> getTypes(StrolchTransaction tx) {
 		return new HashSet<>(this.auditMap.keySet());
 	}
 
 	@Override
-	public Audit getBy(StrolchTransaction tx, String type, Long id) {
+	public synchronized Audit getBy(StrolchTransaction tx, String type, Long id) {
 		return this.auditMap.getElement(type, id);
 	}
 
 	@Override
-	public List<Audit> getAllElements(StrolchTransaction tx, String type, DateRange dateRange) {
+	public synchronized List<Audit> getAllElements(StrolchTransaction tx, String type, DateRange dateRange) {
 		List<Audit> elements = new ArrayList<>();
 
 		Map<Long, Audit> byType = this.auditMap.getMap(type);
@@ -115,14 +116,14 @@ public class CachedAuditTrail implements AuditTrail {
 	}
 
 	@Override
-	public void add(StrolchTransaction tx, Audit audit) {
+	public synchronized void add(StrolchTransaction tx, Audit audit) {
 		this.auditMap.addElement(audit.getElementType(), audit.getId(), audit);
 		// last is to perform DB changes
 		getDao(tx).save(audit);
 	}
 
 	@Override
-	public void addAll(StrolchTransaction tx, List<Audit> audits) {
+	public synchronized void addAll(StrolchTransaction tx, List<Audit> audits) {
 		for (Audit audit : audits) {
 			this.auditMap.addElement(audit.getElementType(), audit.getId(), audit);
 		}
@@ -131,7 +132,7 @@ public class CachedAuditTrail implements AuditTrail {
 	}
 
 	@Override
-	public Audit update(StrolchTransaction tx, Audit audit) {
+	public synchronized Audit update(StrolchTransaction tx, Audit audit) {
 		Audit replacedAudit = this.auditMap.addElement(audit.getElementType(), audit.getId(), audit);
 		// last is to perform DB changes
 		getDao(tx).update(audit);
@@ -139,7 +140,7 @@ public class CachedAuditTrail implements AuditTrail {
 	}
 
 	@Override
-	public List<Audit> updateAll(StrolchTransaction tx, List<Audit> audits) {
+	public synchronized List<Audit> updateAll(StrolchTransaction tx, List<Audit> audits) {
 		List<Audit> replacedAudits = new ArrayList<>();
 		for (Audit audit : audits) {
 			Audit replacedAudit = this.auditMap.addElement(audit.getElementType(), audit.getId(), audit);
@@ -152,14 +153,14 @@ public class CachedAuditTrail implements AuditTrail {
 	}
 
 	@Override
-	public void remove(StrolchTransaction tx, Audit audit) {
+	public synchronized void remove(StrolchTransaction tx, Audit audit) {
 		this.auditMap.removeElement(audit.getElementType(), audit.getId());
 		// last is to perform DB changes
 		getDao(tx).remove(audit);
 	}
 
 	@Override
-	public void removeAll(StrolchTransaction tx, List<Audit> audits) {
+	public synchronized void removeAll(StrolchTransaction tx, List<Audit> audits) {
 		for (Audit audit : audits) {
 			this.auditMap.removeElement(audit.getElementType(), audit.getId());
 		}
@@ -169,7 +170,7 @@ public class CachedAuditTrail implements AuditTrail {
 	}
 
 	@Override
-	public long removeAll(StrolchTransaction tx, String type, DateRange dateRange) {
+	public synchronized long removeAll(StrolchTransaction tx, String type, DateRange dateRange) {
 
 		Map<Long, Audit> byType = this.auditMap.getMap(type);
 		if (byType == null)
diff --git a/src/main/java/li/strolch/agent/impl/CachedElementMap.java b/src/main/java/li/strolch/agent/impl/CachedElementMap.java
index 88f37f4cd..fc7a262bc 100644
--- a/src/main/java/li/strolch/agent/impl/CachedElementMap.java
+++ b/src/main/java/li/strolch/agent/impl/CachedElementMap.java
@@ -46,19 +46,19 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	private Map<String, Map<String, T>> elementMap;
 
 	public CachedElementMap() {
-		this.allKeys = Collections.synchronizedSet(new HashSet<String>());
-		this.elementMap = Collections.synchronizedMap(new HashMap<String, Map<String, T>>());
+		this.allKeys = new HashSet<String>();
+		this.elementMap = new HashMap<String, Map<String, T>>();
 	}
 
 	protected abstract StrolchDao<T> getDao(StrolchTransaction tx);
 
 	@Override
-	public boolean hasType(StrolchTransaction tx, String type) {
+	public synchronized boolean hasType(StrolchTransaction tx, String type) {
 		return this.elementMap.containsKey(type);
 	}
 
 	@Override
-	public boolean hasElement(StrolchTransaction tx, String type, String id) {
+	public synchronized boolean hasElement(StrolchTransaction tx, String type, String id) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return false;
@@ -67,7 +67,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public long querySize(StrolchTransaction tx) {
+	public synchronized long querySize(StrolchTransaction tx) {
 		long size = 0L;
 
 		for (String type : this.elementMap.keySet()) {
@@ -79,7 +79,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public long querySize(StrolchTransaction tx, String type) {
+	public synchronized long querySize(StrolchTransaction tx, String type) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return 0L;
@@ -87,12 +87,12 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public T getTemplate(StrolchTransaction tx, String type) {
+	public synchronized T getTemplate(StrolchTransaction tx, String type) {
 		return getBy(tx, StrolchConstants.TEMPLATE, type);
 	}
 
 	@Override
-	public T getBy(StrolchTransaction tx, String type, String id) {
+	public synchronized T getBy(StrolchTransaction tx, String type, String id) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return null;
@@ -101,7 +101,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public List<T> getAllElements(StrolchTransaction tx) {
+	public synchronized List<T> getAllElements(StrolchTransaction tx) {
 		List<T> allElements = new ArrayList<>();
 		for (String type : this.elementMap.keySet()) {
 			Map<String, T> byType = this.elementMap.get(type);
@@ -112,7 +112,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public List<T> getElementsBy(StrolchTransaction tx, String type) {
+	public synchronized List<T> getElementsBy(StrolchTransaction tx, String type) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return Collections.emptyList();
@@ -120,12 +120,12 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public Set<String> getTypes(StrolchTransaction tx) {
+	public synchronized Set<String> getTypes(StrolchTransaction tx) {
 		return new HashSet<>(this.elementMap.keySet());
 	}
 
 	@Override
-	public Set<String> getAllKeys(StrolchTransaction tx) {
+	public synchronized Set<String> getAllKeys(StrolchTransaction tx) {
 		Set<String> keys = new HashSet<>();
 		for (String type : this.elementMap.keySet()) {
 			Map<String, T> byType = this.elementMap.get(type);
@@ -135,7 +135,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public Set<String> getKeysBy(StrolchTransaction tx, String type) {
+	public synchronized Set<String> getKeysBy(StrolchTransaction tx, String type) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return Collections.emptySet();
@@ -143,7 +143,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public void add(StrolchTransaction tx, T element) {
+	public synchronized void add(StrolchTransaction tx, T element) {
 		DBC.PRE.assertNotNull("Transaction may not be null!", tx); //$NON-NLS-1$
 		DBC.PRE.assertNotNull("Element may not be null!", element); //$NON-NLS-1$
 
@@ -151,7 +151,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public T update(StrolchTransaction tx, T element) {
+	public synchronized T update(StrolchTransaction tx, T element) {
 		DBC.PRE.assertNotNull("Transaction may not be null!", tx); //$NON-NLS-1$
 		DBC.PRE.assertNotNull("Element may not be null!", element); //$NON-NLS-1$
 
@@ -162,48 +162,41 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 			throw new StrolchPersistenceException(msg);
 		}
 
-		T replacedElement;
-		synchronized (byType) {
-			if (byType.remove(element.getId()) == null) {
-				msg = MessageFormat.format(msg, element.getLocator());
-				throw new StrolchPersistenceException(msg);
-			}
-			replacedElement = byType.put(element.getId(), element);
-			getDao(tx).update(element);
+		if (byType.remove(element.getId()) == null) {
+			msg = MessageFormat.format(msg, element.getLocator());
+			throw new StrolchPersistenceException(msg);
 		}
+		T replacedElement = byType.put(element.getId(), element);
+		getDao(tx).update(element);
 
 		return replacedElement;
 	}
 
 	@Override
-	public void remove(StrolchTransaction tx, T element) {
+	public synchronized void remove(StrolchTransaction tx, T element) {
 		DBC.PRE.assertNotNull("Transaction may not be null!", tx); //$NON-NLS-1$
 		DBC.PRE.assertNotNull("Element may not be null!", element); //$NON-NLS-1$
 
 		String msg = "The element {0} can not be removed as it does not exist!"; //$NON-NLS-1$
 
-		synchronized (this.elementMap) {
-			Map<String, T> byType = this.elementMap.get(element.getType());
-			if (byType == null) {
-				msg = MessageFormat.format(msg, element.getLocator());
-				throw new StrolchPersistenceException(msg);
-			}
+		Map<String, T> byType = this.elementMap.get(element.getType());
+		if (byType == null) {
+			msg = MessageFormat.format(msg, element.getLocator());
+			throw new StrolchPersistenceException(msg);
+		}
 
-			synchronized (byType) {
-				if (byType.remove(element.getId()) == null) {
-					msg = MessageFormat.format(msg, element.getLocator());
-					throw new StrolchPersistenceException(msg);
-				}
-				if (byType.isEmpty()) {
-					synchronized (this.elementMap) {
-						if (byType.isEmpty())
-							this.elementMap.remove(element.getType());
-					}
-				}
-				this.allKeys.remove(element.getId());
-				getDao(tx).remove(element);
+		if (byType.remove(element.getId()) == null) {
+			msg = MessageFormat.format(msg, element.getLocator());
+			throw new StrolchPersistenceException(msg);
+		}
+		if (byType.isEmpty()) {
+			synchronized (this.elementMap) {
+				if (byType.isEmpty())
+					this.elementMap.remove(element.getType());
 			}
 		}
+		this.allKeys.remove(element.getId());
+		getDao(tx).remove(element);
 	}
 
 	/**
@@ -214,33 +207,28 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	 * @param element
 	 * @param tx
 	 */
-	void insert(T element, StrolchTransaction tx) {
+	synchronized void insert(T element, StrolchTransaction tx) {
 		if (this.allKeys.contains(element.getId())) {
 			String msg = "An element already exists with the id " + element.getId() //$NON-NLS-1$
 					+ ". Elements of the same class must always have a unique id, regardless of their type!"; //$NON-NLS-1$
 			throw new StrolchPersistenceException(msg);
 		}
 
-		Map<String, T> byType;
-		synchronized (this.elementMap) {
-			byType = this.elementMap.get(element.getType());
-			if (byType == null) {
-				byType = Collections.synchronizedMap(new HashMap<String, T>());
-				this.elementMap.put(element.getType(), byType);
-			}
+		Map<String, T> byType = this.elementMap.get(element.getType());
+		if (byType == null) {
+			byType = Collections.synchronizedMap(new HashMap<String, T>());
+			this.elementMap.put(element.getType(), byType);
 		}
 
-		synchronized (byType) {
-			if (byType.containsKey(element.getId())) {
-				String msg = MessageFormat.format("The element {0} already exists!", element.getLocator()); //$NON-NLS-1$
-				throw new StrolchPersistenceException(msg);
-			}
-
-			byType.put(element.getId(), element);
-			this.allKeys.add(element.getId());
-			if (tx != null)
-				getDao(tx).save(element);
+		if (byType.containsKey(element.getId())) {
+			String msg = MessageFormat.format("The element {0} already exists!", element.getLocator()); //$NON-NLS-1$
+			throw new StrolchPersistenceException(msg);
 		}
+
+		byType.put(element.getId(), element);
+		this.allKeys.add(element.getId());
+		if (tx != null)
+			getDao(tx).save(element);
 	}
 
 	private Map<String, List<T>> sortElementsToType(List<T> elements) {
@@ -257,7 +245,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public void addAll(StrolchTransaction tx, List<T> elements) {
+	public synchronized void addAll(StrolchTransaction tx, List<T> elements) {
 		DBC.PRE.assertNotNull("Transaction may not be null!", tx); //$NON-NLS-1$
 		DBC.PRE.assertNotNull("Elements may not be null!", elements); //$NON-NLS-1$
 
@@ -271,26 +259,22 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 		for (String type : map.keySet()) {
 
 			Map<String, T> byType;
-			synchronized (this.elementMap) {
-				byType = this.elementMap.get(type);
-				if (byType == null) {
-					byType = new HashMap<>();
-					this.elementMap.put(type, byType);
+			byType = this.elementMap.get(type);
+			if (byType == null) {
+				byType = new HashMap<>();
+				this.elementMap.put(type, byType);
+			}
+
+			List<T> newByType = map.get(type);
+			for (T element : newByType) {
+				if (byType.containsKey(element.getId())) {
+					String msg = "An element already exists with the id {0}. Elements of the same class must always have a unique id, regardless of their type!"; //$NON-NLS-1$
+					msg = MessageFormat.format(msg, element.getId());
+					throw new StrolchPersistenceException(msg);
 				}
 
-				List<T> newByType = map.get(type);
-				for (T element : newByType) {
-					synchronized (byType) {
-						if (byType.containsKey(element.getId())) {
-							String msg = "An element already exists with the id {0}. Elements of the same class must always have a unique id, regardless of their type!"; //$NON-NLS-1$
-							msg = MessageFormat.format(msg, element.getId());
-							throw new StrolchPersistenceException(msg);
-						}
-
-						byType.put(element.getId(), element);
-						this.allKeys.add(element.getId());
-					}
-				}
+				byType.put(element.getId(), element);
+				this.allKeys.add(element.getId());
 			}
 		}
 
@@ -299,7 +283,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public List<T> updateAll(StrolchTransaction tx, List<T> elements) {
+	public synchronized List<T> updateAll(StrolchTransaction tx, List<T> elements) {
 		DBC.PRE.assertNotNull("Transaction may not be null!", tx); //$NON-NLS-1$
 		DBC.PRE.assertNotNull("Elements may not be null!", elements); //$NON-NLS-1$
 
@@ -317,24 +301,20 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 		for (String type : map.keySet()) {
 			List<T> list = map.get(type);
 
-			synchronized (this.elementMap) {
-				Map<String, T> byType = this.elementMap.get(type);
-				if (byType == null) {
-					msg = MessageFormat.format(msg, list.get(0).getLocator());
+			Map<String, T> byType = this.elementMap.get(type);
+			if (byType == null) {
+				msg = MessageFormat.format(msg, list.get(0).getLocator());
+				throw new StrolchPersistenceException(msg);
+			}
+
+			for (T element : list) {
+				T replacedElement = byType.remove(element.getId());
+				if (replacedElement == null) {
+					msg = MessageFormat.format(msg, element.getLocator());
 					throw new StrolchPersistenceException(msg);
 				}
-
-				synchronized (byType) {
-					for (T element : list) {
-						T replacedElement = byType.remove(element.getId());
-						if (replacedElement == null) {
-							msg = MessageFormat.format(msg, element.getLocator());
-							throw new StrolchPersistenceException(msg);
-						}
-						byType.put(element.getId(), element);
-						replacedElements.add(replacedElement);
-					}
-				}
+				byType.put(element.getId(), element);
+				replacedElements.add(replacedElement);
 			}
 		}
 
@@ -345,7 +325,7 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public void removeAll(StrolchTransaction tx, List<T> elements) {
+	public synchronized void removeAll(StrolchTransaction tx, List<T> elements) {
 		DBC.PRE.assertNotNull("Transaction may not be null!", tx); //$NON-NLS-1$
 		DBC.PRE.assertNotNull("Elements may not be null!", elements); //$NON-NLS-1$
 
@@ -361,26 +341,22 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 		for (String type : map.keySet()) {
 			List<T> list = map.get(type);
 
-			synchronized (this.elementMap) {
-				Map<String, T> byType = this.elementMap.get(type);
-				if (byType == null) {
-					msg = MessageFormat.format(msg, list.get(0).getLocator());
+			Map<String, T> byType = this.elementMap.get(type);
+			if (byType == null) {
+				msg = MessageFormat.format(msg, list.get(0).getLocator());
+				throw new StrolchPersistenceException(msg);
+			}
+			for (T element : list) {
+				if (byType.remove(element.getId()) == null) {
+					msg = MessageFormat.format(msg, element.getLocator());
 					throw new StrolchPersistenceException(msg);
 				}
-				synchronized (byType) {
-					for (T element : list) {
-						if (byType.remove(element.getId()) == null) {
-							msg = MessageFormat.format(msg, element.getLocator());
-							throw new StrolchPersistenceException(msg);
-						}
-						this.allKeys.remove(element.getId());
+				this.allKeys.remove(element.getId());
 
-						if (byType.isEmpty()) {
-							synchronized (this.elementMap) {
-								if (byType.isEmpty())
-									this.elementMap.remove(type);
-							}
-						}
+				if (byType.isEmpty()) {
+					synchronized (this.elementMap) {
+						if (byType.isEmpty())
+							this.elementMap.remove(type);
 					}
 				}
 			}
@@ -391,21 +367,19 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public long removeAll(StrolchTransaction tx) {
+	public synchronized long removeAll(StrolchTransaction tx) {
 
 		if (this.elementMap.isEmpty())
 			return 0;
 
 		long removed = 0;
 
-		synchronized (this.elementMap) {
-			Set<String> types = this.elementMap.keySet();
-			for (String type : types) {
+		Set<String> types = this.elementMap.keySet();
+		for (String type : types) {
 
-				Map<String, T> byType = this.elementMap.get(type);
-				removed += byType.size();
-				byType.clear();
-			}
+			Map<String, T> byType = this.elementMap.get(type);
+			removed += byType.size();
+			byType.clear();
 		}
 
 		// last is to perform DB changes
@@ -420,22 +394,20 @@ public abstract class CachedElementMap<T extends StrolchRootElement> implements
 	}
 
 	@Override
-	public long removeAllBy(StrolchTransaction tx, String type) {
+	public synchronized long removeAllBy(StrolchTransaction tx, String type) {
 
 		long removed = 0;
 		String msg = "The elements with type {0} can not be removed as they do not exist!"; //$NON-NLS-1$
 
-		synchronized (this.elementMap) {
-			Map<String, T> byType = this.elementMap.get(type);
-			if (byType == null) {
-				msg = MessageFormat.format(msg, type);
-				throw new StrolchPersistenceException(msg);
-			}
-
-			removed = byType.size();
-			byType.clear();
+		Map<String, T> byType = this.elementMap.get(type);
+		if (byType == null) {
+			msg = MessageFormat.format(msg, type);
+			throw new StrolchPersistenceException(msg);
 		}
 
+		removed = byType.size();
+		byType.clear();
+
 		// last is to perform DB changes
 		long daoRemoved = getDao(tx).removeAllBy(type);
 
diff --git a/src/main/java/li/strolch/persistence/inmemory/InMemoryAuditDao.java b/src/main/java/li/strolch/persistence/inmemory/InMemoryAuditDao.java
index a0ab17153..597f4c978 100644
--- a/src/main/java/li/strolch/persistence/inmemory/InMemoryAuditDao.java
+++ b/src/main/java/li/strolch/persistence/inmemory/InMemoryAuditDao.java
@@ -39,7 +39,7 @@ public class InMemoryAuditDao implements AuditDao {
 	}
 
 	@Override
-	public boolean hasElement(String type, Long id) {
+	public synchronized boolean hasElement(String type, Long id) {
 		Map<Long, Audit> byType = this.auditMap.getMap(type);
 		if (byType == null)
 			return false;
@@ -47,7 +47,7 @@ public class InMemoryAuditDao implements AuditDao {
 	}
 
 	@Override
-	public long querySize(DateRange dateRange) {
+	public synchronized long querySize(DateRange dateRange) {
 		long size = 0L;
 
 		for (String type : this.auditMap.keySet()) {
@@ -62,7 +62,7 @@ public class InMemoryAuditDao implements AuditDao {
 	}
 
 	@Override
-	public long querySize(String type, DateRange dateRange) {
+	public synchronized long querySize(String type, DateRange dateRange) {
 		long size = 0L;
 		Map<Long, Audit> byType = this.auditMap.getMap(type);
 		for (Audit audit : byType.values()) {
@@ -73,17 +73,17 @@ public class InMemoryAuditDao implements AuditDao {
 	}
 
 	@Override
-	public Audit queryBy(String type, Long id) {
+	public synchronized Audit queryBy(String type, Long id) {
 		return this.auditMap.getElement(type, id);
 	}
 
 	@Override
-	public Set<String> queryTypes() {
+	public synchronized Set<String> queryTypes() {
 		return this.auditMap.keySet();
 	}
 
 	@Override
-	public List<Audit> queryAll(String type, DateRange dateRange) {
+	public synchronized List<Audit> queryAll(String type, DateRange dateRange) {
 		List<Audit> audits = new ArrayList<>();
 		Map<Long, Audit> byType = this.auditMap.getMap(type);
 		if (byType == null)
@@ -97,43 +97,43 @@ public class InMemoryAuditDao implements AuditDao {
 	}
 
 	@Override
-	public void save(Audit audit) {
+	public synchronized void save(Audit audit) {
 		this.auditMap.addElement(audit.getElementType(), audit.getId(), audit);
 	}
 
 	@Override
-	public void saveAll(List<Audit> audits) {
+	public synchronized void saveAll(List<Audit> audits) {
 		for (Audit audit : audits) {
 			this.auditMap.addElement(audit.getElementType(), audit.getId(), audit);
 		}
 	}
 
 	@Override
-	public void update(Audit audit) {
+	public synchronized void update(Audit audit) {
 		this.auditMap.addElement(audit.getElementType(), audit.getId(), audit);
 	}
 
 	@Override
-	public void updateAll(List<Audit> audits) {
+	public synchronized void updateAll(List<Audit> audits) {
 		for (Audit audit : audits) {
 			this.auditMap.addElement(audit.getElementType(), audit.getId(), audit);
 		}
 	}
 
 	@Override
-	public void remove(Audit audit) {
+	public synchronized void remove(Audit audit) {
 		this.auditMap.removeElement(audit.getElementType(), audit.getId());
 	}
 
 	@Override
-	public void removeAll(List<Audit> audits) {
+	public synchronized void removeAll(List<Audit> audits) {
 		for (Audit audit : audits) {
 			this.auditMap.removeElement(audit.getElementType(), audit.getId());
 		}
 	}
 
 	@Override
-	public long removeAll(String type, DateRange dateRange) {
+	public synchronized long removeAll(String type, DateRange dateRange) {
 
 		Map<Long, Audit> byType = this.auditMap.getMap(type);
 		if (byType == null)
diff --git a/src/main/java/li/strolch/persistence/inmemory/InMemoryDao.java b/src/main/java/li/strolch/persistence/inmemory/InMemoryDao.java
index ae7277cbe..c18a827fa 100644
--- a/src/main/java/li/strolch/persistence/inmemory/InMemoryDao.java
+++ b/src/main/java/li/strolch/persistence/inmemory/InMemoryDao.java
@@ -21,7 +21,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public boolean hasElement(String type, String id) {
+	public synchronized boolean hasElement(String type, String id) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return false;
@@ -29,7 +29,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public long querySize() {
+	public synchronized long querySize() {
 		long size = 0;
 		for (String type : this.elementMap.keySet()) {
 			Map<String, T> byType = this.elementMap.get(type);
@@ -39,7 +39,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public long querySize(String type) {
+	public synchronized long querySize(String type) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return 0;
@@ -47,7 +47,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public Set<String> queryKeySet() {
+	public synchronized Set<String> queryKeySet() {
 
 		Set<String> keySet = new HashSet<>();
 		for (String type : this.elementMap.keySet()) {
@@ -61,7 +61,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public Set<String> queryKeySet(String type) {
+	public synchronized Set<String> queryKeySet(String type) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return new HashSet<>(0);
@@ -69,12 +69,12 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public Set<String> queryTypes() {
+	public synchronized Set<String> queryTypes() {
 		return new HashSet<>(this.elementMap.keySet());
 	}
 
 	@Override
-	public T queryBy(String type, String id) {
+	public synchronized T queryBy(String type, String id) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return null;
@@ -82,7 +82,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public List<T> queryAll() {
+	public synchronized List<T> queryAll() {
 		List<T> elements = new ArrayList<>();
 		for (String type : this.elementMap.keySet()) {
 			Map<String, T> byType = this.elementMap.get(type);
@@ -95,7 +95,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public List<T> queryAll(String type) {
+	public synchronized List<T> queryAll(String type) {
 		Map<String, T> byType = this.elementMap.get(type);
 		if (byType == null)
 			return new ArrayList<>(0);
@@ -103,7 +103,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public void save(T element) {
+	public synchronized void save(T element) {
 		Map<String, T> byType = this.elementMap.get(element.getType());
 		if (byType == null) {
 			byType = new HashMap<>();
@@ -120,14 +120,14 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public void saveAll(List<T> elements) {
+	public synchronized void saveAll(List<T> elements) {
 		for (T element : elements) {
 			save(element);
 		}
 	}
 
 	@Override
-	public void update(T element) {
+	public synchronized void update(T element) {
 		Map<String, T> byType = this.elementMap.get(element.getType());
 		if (byType == null) {
 			byType = new HashMap<>();
@@ -138,14 +138,14 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public void updateAll(List<T> elements) {
+	public synchronized void updateAll(List<T> elements) {
 		for (T element : elements) {
 			update(element);
 		}
 	}
 
 	@Override
-	public void remove(T element) {
+	public synchronized void remove(T element) {
 		Map<String, T> byType = this.elementMap.get(element.getType());
 		if (byType != null) {
 			byType.remove(element.getId());
@@ -157,14 +157,14 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public void removeAll(List<T> elements) {
+	public synchronized void removeAll(List<T> elements) {
 		for (T element : elements) {
 			remove(element);
 		}
 	}
 
 	@Override
-	public long removeAll() {
+	public synchronized long removeAll() {
 		long removed = 0;
 
 		Set<String> keySet = new HashSet<String>(this.elementMap.keySet());
@@ -178,7 +178,7 @@ public class InMemoryDao<T extends StrolchElement> implements StrolchDao<T> {
 	}
 
 	@Override
-	public long removeAllBy(String type) {
+	public synchronized long removeAllBy(String type) {
 		Map<String, T> byType = this.elementMap.remove(type);
 		if (byType == null)
 			return 0;