diff --git a/subcmds/init.py b/subcmds/init.py
index d86c49a..a32eaae 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -131,7 +131,9 @@
 
     m.Sync_LocalHalf()
     if is_new or m.CurrentBranch is None:
-      m.StartBranch('default')
+      if not m.StartBranch('default'):
+        print >>sys.stderr, 'fatal: cannot create default in manifest'
+        sys.exit(1)
 
   def _LinkManifest(self, name):
     if not name:
diff --git a/subcmds/start.py b/subcmds/start.py
index 4eb3e47..deced7c 100644
--- a/subcmds/start.py
+++ b/subcmds/start.py
@@ -47,5 +47,13 @@
       print >>sys.stderr, "error: '%s' is not a valid name" % nb
       sys.exit(1)
 
+    err = []
     for project in self.GetProjects(args[1:]):
-      project.StartBranch(nb)
+      if not project.StartBranch(nb):
+        err.append(project)
+
+    if err:
+      err.sort()
+      for p in err:
+        print >>sys.stderr, "error: cannot start in %s" % p.relpath
+      sys.exit(1)