diff --git a/src/main/java/eu/openaire/urls_worker/plugins/PublicationsRetrieverPlugin.java b/src/main/java/eu/openaire/urls_worker/plugins/PublicationsRetrieverPlugin.java
index 32e81c3..3b8d8ec 100644
--- a/src/main/java/eu/openaire/urls_worker/plugins/PublicationsRetrieverPlugin.java
+++ b/src/main/java/eu/openaire/urls_worker/plugins/PublicationsRetrieverPlugin.java
@@ -130,6 +130,9 @@ public class PublicationsRetrieverPlugin {
             logger.warn(numFailedTasks + " tasks failed, from assignments_" + assignmentRequestCounter);
         addUrlReportsToWorkerReport();
         callableTasks.clear(); // Reset the thread-tasks-list for the next batch.
+
+        UrlUtils.docOrDatasetUrlsWithIDs.clear();   // This HashTable is useful only for a single assignments-batch.
+        // In the next batch, the previously stored files might have been already uploaded by the Controller and deleted by the worker. Also, they will be stored in a different directory anyway.
     }
 
 
@@ -151,11 +154,11 @@ public class PublicationsRetrieverPlugin {
                 status = UrlReport.StatusType.accessible;
                 if ( comment.contains(UrlUtils.alreadyDownloadedByIDMessage) ) {
                     // The file of this docUrl was already downloaded by another docUrl.
-                    String previousId = comment.substring(UrlUtils.alreadyDownloadedByIDMessage.length() +1);
-                    //logger.debug("previousId: " + previousId);    // DEBUG!
+                    String initialId = comment.substring(UrlUtils.alreadyDownloadedByIDMessage.length());   // The fileName starts right after the "message".
+                    //logger.debug("initialId: " + initialId);    // DEBUG!
                     // Search that ID inside the list and if that instance gave the docUrl (there might be multiple ID instances) then get the file-location.
                     for ( DataToBeLogged data_2 : FileUtils.dataToBeLoggedList ) {
-                        if ( data_2.getUrlId().equals(previousId) && data_2.getWasDocumentOrDatasetAccessible().equals("true") ) {
+                        if ( data_2.getUrlId().equals(initialId) && data_2.getWasDocumentOrDatasetAccessible().equals("true") ) {
                             fileLocation = data_2.getComment();
                             size = data_2.getSize();
                             hash = data_2.getHash();