diff --git a/.gitignore b/.gitignore
index face70b8..636a599b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,3 +17,7 @@ Makefile
 .pydevproject
 .project
 .settings
+
+# virtual environment:
+lib64
+pip-selfcheck.json
diff --git a/sc/social/like/upgrades/v3046/__init__.py b/sc/social/like/upgrades/v3046/__init__.py
index a0446220..4a08d7a0 100644
--- a/sc/social/like/upgrades/v3046/__init__.py
+++ b/sc/social/like/upgrades/v3046/__init__.py
@@ -5,6 +5,15 @@
 
 import transaction
 
+try:
+    # this exception must be resubmitted:
+    from ZODB.POSException import ConflictError
+except ImportError:
+    # we don't really *require* this;
+    #  if we don't have it, a dummy exception will do:
+    class ConflictError(Exception):
+        pass
+
 
 def reindex_catalog(setup_tool):
     """Reindex objects to fix interfaces on the catalog."""
@@ -16,13 +25,24 @@ def reindex_catalog(setup_tool):
     results = catalog()
     logger.info(u'Found {0} objects'.format(len(results)))
     n = 0
+    errors = 0
     for obj in get_valid_objects(results):
-        catalog.catalog_object(obj, idxs=['object_provides'], update_metadata=False)
+        try:
+            catalog.catalog_object(obj, idxs=['object_provides'], update_metadata=False)
+        except ConflictError:
+            raise
+        except Exception as e:
+            errors += 1
+            logger.error('{0!r} reindexing {1!r}'.format(e, obj))
+            if test:
+                raise
         n += 1
         if n % 1000 == 0 and not test:
             transaction.commit()
             logger.info('{0} items processed.'.format(n))
 
     if not test:
+        if errors:
+            logger.info('{0} errors occured.'.format(errors))
         transaction.commit()
     logger.info('Done.')
diff --git a/sc/social/like/utils.py b/sc/social/like/utils.py
index c011533b..f105e958 100644
--- a/sc/social/like/utils.py
+++ b/sc/social/like/utils.py
@@ -117,6 +117,8 @@ def get_valid_objects(brains):
             obj = b.getObject()
         except KeyError:
             obj = None
+        except AttributeError:
+            obj = None
 
         if obj is None:  # warn on broken entries in the catalog
             msg = u'Skipping invalid reference in the catalog: {0}'