Fresh installation on the same server where another core version was installed gives error I have my own remote server to play around. I gave Drupal 8 a go but decided today to delete it from my server and install Drupal 7.56 again.

So I deleted all files via FTP and deleted all tables in phpMyAdmin, uploaded the Drupal 7.56 files from a fresh package I downloaded from drupal.org but ran into this issue:

When running through the process of install.php I suddenly get these 2 error: 

Notice: Undefined variable: app_root in include_once() (line 690 of /var/www/clients/client1/web3/web/sites/default/settings.php).
Notice: Undefined variable: site_path in include_once() (line 690 of /var/www/clients/client1/web3/web/sites/default/settings.php).


So, after some Googling I found out it might have to do with the setting.php file of Drupal 8. The thing I don't understand is how this fresh install can search for the settings.php file of the Drupal 8 installation whilst I deleted every single file and table? 

I checked my settings.php file of the Drupal 7 installation and there are only 648 lines, so I have no idea where to go searching...
After you install Drupal, automatically Drupal set sites/default to 555 and settings/default/settings.php to 444 , So it means they haven't deleted . 

my suggestion is to change the permission for them, them delete settings.php (and make sure you delete it correctly ), and when you got insure of deleting everything Setup Drupal 7.56 again.