diff --git a/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java b/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
index b56488a..7d08097 100644
--- a/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
+++ b/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendFactory.java
@@ -111,7 +111,7 @@ public abstract class AccountingPersistenceBackendFactory {
 	};
 	
 	protected static AccountingPersistenceBackend rediscoverAccountingPersistenceBackend(AccountingPersistenceBackend actual, String scope){
-		long now = Calendar.getInstance().getTimeInMillis();
+		Long now = Calendar.getInstance().getTimeInMillis();
 		Long lastCheckTimestamp = fallbackLastCheck.get(scope);
 		logger.trace("Last check was {}", lastCheckTimestamp);
 		
@@ -122,8 +122,13 @@ public abstract class AccountingPersistenceBackendFactory {
 			try {
 				lock.lock();
 				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");
+					return actual;
+				}
 				fallbackLastCheck.put(scope, now);
-				lastCheckTimestamp = fallbackLastCheck.get(scope);
 				lock.unlock();
 				
 				AccountingPersistenceBackend discoveredPersistenceBackend = discoverAccountingPersistenceBackend(scope);
diff --git a/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendMonitor.java b/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendMonitor.java
index c4dc33d..608b74f 100644
--- a/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendMonitor.java
+++ b/src/main/java/org/gcube/accounting/persistence/AccountingPersistenceBackendMonitor.java
@@ -26,6 +26,7 @@ public class AccountingPersistenceBackendMonitor implements Runnable {
 	private final static Logger logger = LoggerFactory.getLogger(AccountingPersistenceBackendMonitorTest.class);
 	
 	private final static String ELABORATION_FILE_SUFFIX = ".ELABORATION";
+	private final static String ELABORATION_FILE_NOT_DELETED_SUFFIX = ".ELABORATION.NOT-DELETED";
 	
 	protected final ScheduledExecutorService scheduler;
 	
@@ -44,8 +45,7 @@ public class AccountingPersistenceBackendMonitor implements Runnable {
 		    		UsageRecord usageRecord = BasicUsageRecord.getUsageRecord(line);
 		    		accountingPersistenceBackend.accountWithFallback(usageRecord);
 		    	} catch(Exception e){
-		    		logger.error("", e);
-		    		// TODO write line on file
+		    		logger.error("Line {} will be lost", line, e);
 		    	}
 		    }
 		} catch (FileNotFoundException e) {
@@ -74,6 +74,13 @@ public class AccountingPersistenceBackendMonitor implements Runnable {
 		
 		if(elaborationFile!=null){
 			elaborateFile(elaborationFile);
+			boolean deleted = elaborationFile.delete();
+			if(!deleted){
+				logger.debug("Failed to delete file {}", elaborationFile.getAbsolutePath());
+				File elaborationFileNotDeleted = new File(elaborationFile.getAbsolutePath()+ELABORATION_FILE_NOT_DELETED_SUFFIX);
+				elaborationFile.renameTo(elaborationFileNotDeleted);
+			}
+			
 		}
 		
 	}