diff --git a/lib/redmine_dmsf/webdav/project_resource.rb b/lib/redmine_dmsf/webdav/project_resource.rb
index 8a982f7a..1f18b2e8 100644
--- a/lib/redmine_dmsf/webdav/project_resource.rb
+++ b/lib/redmine_dmsf/webdav/project_resource.rb
@@ -116,15 +116,18 @@ module RedmineDmsf
 	      self.project.id if self.project
       end
 
+      # Characters that MATCH this regex will be replaced with dots, no more than one dot in a row.
+      INVALID_CHARACTERS = /[\/\\\?":<>#%\*\[\]]/.freeze # = / \ ? " : < > # % * [ ]
+      
       def self.create_project_name(p)
         use_project_names = Setting.plugin_redmine_dmsf['dmsf_webdav_use_project_names']
         if use_project_names
           # 1. Invalid characters are replaced with a dot.
           # 2. Two or more dots in a row are replaced with a single dot.
           # (3. Windows WebClient does not like a dot at the end, but since the project id tag is appended this is not a problem.)
-          "#{p.name.gsub(DmsfFolder::INVALID_CHARACTERS, ".").gsub(/\.{2,}/, '.')} #{p.id}" unless p.nil?
+          "#{p.name.gsub(INVALID_CHARACTERS, '.').gsub(/\.{2,}/, '.')} #{p.id}" if p
         else
-          p.identifier unless p.nil?
+          p.identifier if p
         end
       end
     end