Hello,

We are using the standard .Net password generator. However, this method is used in the source code, so without a source code license it isn't that easy to change this behavior. But you can modify the code of the logon web part. You can customize the btnPasswdRetrieval_Click method to generate a password just with alphanumerical characters and send manually an e-mail to the user, who tried to login. Please note that you have to reset and change the password for the user also in the database. For more information I would suggest you to check our Developer's guide and our API reference.

Best regards,
Boris Pocatko