diff --git a/lib/ruote/storage/base.rb b/lib/ruote/storage/base.rb
index 53e3f8ba..26d73dd0 100644
--- a/lib/ruote/storage/base.rb
+++ b/lib/ruote/storage/base.rb
@@ -278,6 +278,7 @@ def clear
     # the process.
     #
     def remove_process(wfid)
+      return if wfid.nil?
 
       2.times do
         # two passes
diff --git a/test/functional/storage.rb b/test/functional/storage.rb
index bdc21cd6..c6edfe79 100644
--- a/test/functional/storage.rb
+++ b/test/functional/storage.rb
@@ -580,6 +580,14 @@ def test_remove_process
     assert_equal 1, @s.get_many('errors').size
     assert_equal 1, @s.get_trackers['trackers'].size
 
+    @s.remove_process(nil)
+
+    assert_equal 6, @s.get_many('expressions').size
+    assert_equal 1, @s.get_many('schedules').size
+    assert_equal 1, @s.get_many('workitems').size
+    assert_equal 1, @s.get_many('errors').size
+    assert_equal 1, @s.get_trackers['trackers'].size
+
   ensure
     dboard.shutdown rescue nil
   end