Internal links no longer working. Getting MAMP virtual host info instead
Since turning off Clean URLs seems to at least be a work around for your issue, it sounds that you have not correctly configured Clean URLs. To correctly enable/configure Clean URLs, refer to Configure Clean URLs in the installation guide.

If you're not familiar with Clean URLs yet, I suggest to review that documentation (for the version of Drupal that you're using) and make sure your server is correctly configured before proceeding.

Here is a summary of common steps/issues:


With Apache HTTPD as web-server, you have to enable mod_rewrite and configure the necessary rewrite rules in the .htaccess file.
Usually, theses rules are applied automatically, when mod_rewrite is enabled. But in some cases, the AllowOverride directive is too restrictive to allow this.