diff --git a/bitbake/lib/bb/checksum.py b/bitbake/lib/bb/checksum.py
index be4ab68915..84289208f4 100644
--- a/bitbake/lib/bb/checksum.py
+++ b/bitbake/lib/bb/checksum.py
@@ -120,13 +120,15 @@ class FileChecksumCache(MultiProcessCache):
                             checksums.extend(checksum_dir(f))
                     else:
                         checksum = checksum_file(f)
-                        checksums.append((f, checksum))
+                        if checksum:
+                            checksums.append((f, checksum))
             elif os.path.isdir(pth):
                 if not os.path.islink(pth):
                     checksums.extend(checksum_dir(pth))
             else:
                 checksum = checksum_file(pth)
-                checksums.append((pth, checksum))
+                if checksum:
+                    checksums.append((pth, checksum))
 
         checksums.sort(key=operator.itemgetter(1))
         return checksums