diff --git a/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java b/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
index 611ae9b..6b5a742 100644
--- a/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
+++ b/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
@@ -115,23 +115,23 @@ public abstract class AccountingPersistenceBackendFactory {
 		Long now = Calendar.getInstance().getTimeInMillis();
 		Long lastCheckTimestamp = fallbackLastCheck.get(scope);
 		logger.debug("Last check for scope {} was {}", scope, lastCheckTimestamp);
-		
-		if( (lastCheckTimestamp + FALLBACK_RETRY_TIME) <= now ){
-			logger.debug("The {} for scope {} is {}. Is time to rediscover if there is another possibility.",
+		boolean myTurn = false;
+		synchronized (accountingPersistenceBackends) {
+			if( (lastCheckTimestamp + FALLBACK_RETRY_TIME) <= now ){
+				logger.debug("The {} for scope {} is {}. Is time to rediscover if there is another possibility.",
 					AccountingPersistenceBackend.class.getSimpleName(), scope, actual.getClass().getSimpleName());
-			
+				logger.trace("Renewing Last check Timestamp. The next one will be {}", now);
+				fallbackLastCheck.put(scope, now);
+				myTurn=true;
+				logger.debug("I win. It is my turn to rediscover {} in scope {}", 
+						AccountingPersistenceBackend.class.getSimpleName(), scope);
+			}
+		}
+		
+		if(myTurn){
 			AccountingPersistenceBackend discoveredPersistenceBackend = discoverAccountingPersistenceBackend(scope);
 			
 			synchronized (accountingPersistenceBackends) {
-				logger.trace("Renewing Last check Timestamp. The next one will be {}", now);
-				Long reCheckTimestamp = fallbackLastCheck.get(scope);
-				if(lastCheckTimestamp.compareTo(reCheckTimestamp)!=0){
-					// Someone else arrived here before. Stopping to try to 
-					logger.debug("Someone else arrived here before. Stopping to try to rediscover AccountingPersistenceBackend and getting the current");
-					return accountingPersistenceBackends.get(scope);
-				}
-				
-				fallbackLastCheck.put(scope, now);
 				if(discoveredPersistenceBackend!=null){
 					/*
 					 * Passing the aggregator to the new AccountingPersistenceBackend