diff --git a/tools_webrtc/autoroller/roll_deps.py b/tools_webrtc/autoroller/roll_deps.py
index 2e9a1c2cfe..77dd7d8d73 100755
--- a/tools_webrtc/autoroller/roll_deps.py
+++ b/tools_webrtc/autoroller/roll_deps.py
@@ -261,7 +261,9 @@ def BuildDepsentryDict(deps_dict):
 def _FindChangedCipdPackages(path, old_pkgs, new_pkgs):
   pkgs_equal = ({p['package'] for p in old_pkgs} ==
       {p['package'] for p in new_pkgs})
-  assert pkgs_equal, 'Old: %s\n New: %s' % (old_pkgs, new_pkgs)
+  assert pkgs_equal, ('Old: %s\n New: %s.\nYou need to do a manual roll '
+                      'and remove/add entries in DEPS so the old and new '
+                      'list match.' % (old_pkgs, new_pkgs))
   for old_pkg in old_pkgs:
     for new_pkg in new_pkgs:
       old_version = old_pkg['version']