diff --git a/swh/loader/package/loader.py b/swh/loader/package/loader.py
--- a/swh/loader/package/loader.py
+++ b/swh/loader/package/loader.py
@@ -331,6 +331,11 @@
                             # FIXME: This should be release. cf. D409
                             revision = self.build_revision(
                                 p_info['raw'], uncompressed_path)
+                            if not revision:
+                                # Some artifacts are missing intrinsic metadata
+                                # skipping those
+                                continue
+
                             revision.update({
                                 'synthetic': True,
                                 'directory': directory.hash,
diff --git a/swh/loader/package/npm/loader.py b/swh/loader/package/npm/loader.py
--- a/swh/loader/package/npm/loader.py
+++ b/swh/loader/package/npm/loader.py
@@ -77,6 +77,8 @@
     def build_revision(
             self, a_metadata: Dict, uncompressed_path: str) -> Dict:
         i_metadata = extract_intrinsic_metadata(uncompressed_path)
+        if not i_metadata:
+            return {}
         # from intrinsic metadata
         author = extract_npm_package_author(i_metadata)
         message = i_metadata['version'].encode('ascii')
diff --git a/swh/loader/package/pypi/loader.py b/swh/loader/package/pypi/loader.py
--- a/swh/loader/package/pypi/loader.py
+++ b/swh/loader/package/pypi/loader.py
@@ -74,6 +74,8 @@
     def build_revision(
             self, a_metadata: Dict, uncompressed_path: str) -> Dict:
         i_metadata = extract_intrinsic_metadata(uncompressed_path)
+        if not i_metadata:
+            return {}
 
         # from intrinsic metadata
         name = i_metadata['version']