You might check into the Macro Signatures documentation. In there, it talks about having a key in your web.config that is used at the hash string salt. If this key doesn't exist, then the database connection string is used as a hash string salt. So if you change your connection string then all of your signed macros become invalid and you have to resign your macros as Yehuda mentions. One way to not sign your macros is to use an @ symbol prior to closing the macro. {% CurrentDocument.NodeAliasPath @%}