I experienced a very strange issue with Drupal 8 (no issues with other CMS programs, just 8). I am using IIS and My SQL for this setup. This error occurs with a new database, and a default settings, where the database has not even been implemented into the settings.php yet.
The following is what has occurred: At the database configuration page, I entered the database information, (select My SQL, database name, username, password, host, port number). Once the information is filled, I select "Save and Continue". Then, The page loads for a couple minutes; stating "waiting for localhost" at the bottom of the browser. Next, I am leaded to a page stating "Drupal already installed". So I delete the settings, and create a new database. I refilled the database information at the Database configuration page, and the error occurred again, stating "Drupal already installed". I redo the process until about the 5th try, Drupal installs displaying the loading bar.
Why does it say downloaded already, but then downloads after redoing a couple tries? If anyone knows why this occurs, feel free to let me know. I am trying to fix this.
Thank you,