diff --git a/lib/redmine_dmsf/webdav/dmsf_resource.rb b/lib/redmine_dmsf/webdav/dmsf_resource.rb
index 199d0cf4..c3c9ff78 100644
--- a/lib/redmine_dmsf/webdav/dmsf_resource.rb
+++ b/lib/redmine_dmsf/webdav/dmsf_resource.rb
@@ -454,6 +454,7 @@ module RedmineDmsf
       def lock(args)
         if parent.nil? || ((parent.projectless_path != '/') && (!parent.exist?))
           e = DAV4Rack::LockFailure.new
+          puts ">>> Conflict 1 #{parent.nil?} #{parent.projectless_path} #{parent.exist?}"
           e.add_failure @path, Conflict
           raise e
         end
@@ -482,6 +483,7 @@ module RedmineDmsf
               if http_if.blank?
                 e = DAV4Rack::LockFailure.new
                 e.add_failure @path, Conflict
+                puts ">>> Conflict 2 #{http_if}"
                 raise e
               end
               l = nil
@@ -491,6 +493,7 @@ module RedmineDmsf
               unless l
                 e = DAV4Rack::LockFailure.new
                 e.add_failure @path, Conflict
+                puts ">>> Conflict 3 #{$1}"
                 raise e
               end
               l.expires_at = Time.current + 1.week
@@ -510,6 +513,7 @@ module RedmineDmsf
         rescue DmsfLockError
           e = DAV4Rack::LockFailure.new
           e.add_failure @path, Conflict
+          puts ">>> Conflict 4 DmsfLockError #{@path}"
           raise e
         end
       end