diff --git a/lib/tasks/quote_strings_with_invalid_characters_in_legacy_journals.rake b/lib/tasks/quote_strings_with_invalid_characters_in_legacy_journals.rake
new file mode 100644
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+++ b/lib/tasks/quote_strings_with_invalid_characters_in_legacy_journals.rake
@@ -0,0 +1,61 @@
+#-- encoding: UTF-8
+#-- copyright
+# OpenProject is a project management system.
+#
+# Copyright (C) 2012-2013 the OpenProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# See doc/COPYRIGHT.rdoc for more details.
+#++
+
+require_relative '../../db/migrate/migration_utils/timelines'
+
+namespace :migrations do
+  namespace :journals do
+    desc "Quotes all strings starting with an invalid character in column 'changed_data' of table 'legacy_journals'"
+    task :quote_strings_with_invalid_characters_in_legacy_journals => :environment do |task|
+      quoter = InvalidChangedDataStringQuoter.new
+
+      quoter.quote_strings_with_invalid_characters
+    end
+
+    private
+
+    class InvalidChangedDataStringQuoter < ActiveRecord::Migration
+      include Migration::Utils
+
+      def quote_strings_with_invalid_characters
+        say_with_time_silently "Quote journal strings with invalid characters" do
+          update_column_values('legacy_journals',
+                               ['changed_data'],
+                               quote_invalid_strings,
+                               invalid_changed_data_filter)
+        end
+      end
+
+      private
+
+      def invalid_changed_data_filter
+        "changed_data LIKE '%- ,%'"
+      end
+
+      INVALID_STARTING_CHARACTER_REGEX = /(?<start>\n- )(?<text>,.*)(?<end>\n.*:)/
+
+      def quote_invalid_strings
+        Proc.new do |row|
+          changed_data = row['changed_data']
+
+          quoted_changed_data = changed_data.gsub(INVALID_STARTING_CHARACTER_REGEX) do |m|
+            "#{$1}\"#{$2}\"#{$3}"
+          end
+
+          row['changed_data'] = quoted_changed_data
+
+          UpdateResult.new(row, changed_data != quoted_changed_data)
+        end
+      end
+    end
+  end
+end