diff --git a/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java b/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
index 785202b..304a85b 100644
--- a/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
+++ b/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
@@ -119,13 +119,12 @@ public abstract class AccountingPersistenceBackendFactory {
 			logger.debug("The {} for scope {} is {}. Is time to rediscover if there is another possibility.",
 					AccountingPersistenceBackend.class.getSimpleName(), scope, actual.getClass().getSimpleName());
 			
-			lock.lock();
 			try {
-				logger.trace("Renewing Last check Timestamp. The next one will be {}", now);
-				fallbackLastCheck.put(scope, now);
-				lastCheckTimestamp = fallbackLastCheck.get(scope);
+				
 				
 				AccountingPersistenceBackend discoveredPersistenceBackend = discoverAccountingPersistenceBackend(scope);
+				
+				lock.lock();
 				if(discoveredPersistenceBackend!=null){
 					// Passing the aggregator to the new  AccountingPersistenceBackend
 					// so that the buffered records will be persisted with the new method
@@ -143,6 +142,10 @@ public abstract class AccountingPersistenceBackendFactory {
 					}
 					lock.unlock();
 					return discoveredPersistenceBackend;
+				}else{
+					logger.trace("Renewing Last check Timestamp. The next one will be {}", now);
+					fallbackLastCheck.put(scope, now);
+					lastCheckTimestamp = fallbackLastCheck.get(scope);
 				}
 			}finally {
 				lock.unlock();
@@ -159,7 +162,7 @@ public abstract class AccountingPersistenceBackendFactory {
 		return actual;
 	}
 	
-	protected static synchronized AccountingPersistenceBackend getPersistenceBackend() {
+	protected static AccountingPersistenceBackend getPersistenceBackend() {
 		String scope = ScopeProvider.instance.get();
 		
 		if(scope==null){