I am trying to upgrade a working 6.26 installation to 7.x. I followed the update instructions to the letter and got everything uploaded and edited. When I tried to run the upgrade.php script, it immediately forwarded me to install.php and displayed this:


Drupal already installed

To start over, you must empty your existing database.
To install to a different database, edit the appropriate settings.php file in the sites folder.
To upgrade an existing installation, proceed to the update script.
View your existing site.

Clicking on the "update script" link just throws the same error - it's just a loop.

Any ideas? I have read that dropping all the tables can solve this problem, but I would really like to preserve my data.

Thanks.