Just a notice to everyone Microsoft seems to have disabled the http://user:firstname.lastname@example.org/ thing in the latest patch for internet explorer. So if your login forms send your customers to an url like that they will get a invalid syntax error! It took me ages to track this problem down. Many customers were complaining to me about getting this error and could find no problem. Today I updated my own PC with windows update, downloaded the IE service pack patch and i noticed it.