diff --git a/swh/scanner/scanner.py b/swh/scanner/scanner.py
--- a/swh/scanner/scanner.py
+++ b/swh/scanner/scanner.py
@@ -88,7 +88,11 @@
     dirpath, dnames, fnames = next(os.walk(path))
     for node in itertools.chain(dnames, fnames):
         sub_path = PosixPath(dirpath).joinpath(node)
-        yield (sub_path, pid_of(sub_path))
+        sub_path_pid = pid_of(sub_path)
+        # ensure the persistent identifier exists
+        # for example, a broken link won't return a pid
+        if sub_path_pid:
+            yield (sub_path, sub_path_pid)
 
 
 async def parse_path(