diff --git a/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/UploadingCommand.java b/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/UploadingCommand.java
index 79a3f1e9bd57c19d6dbdab7c0d20e8b676d866c5..3fe1f10addde112594a697b461feb3dab86fe420 100644
--- a/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/UploadingCommand.java
+++ b/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/UploadingCommand.java
@@ -444,6 +444,12 @@ class UploadingCommand implements IDataSetCommand
                     notificationLog.error("Couldn't add data set '" + externalData.getCode()
                             + "' to zip file.", ex);
                     return false;
+                } finally
+                {
+                    if (root != null)
+                    {
+                        root.close();
+                    }
                 }
             }
             return true;