I'm trying to run a civicrm core module upgrade on a drupal 7 site. I follow all of the posted instructions, but when I run the civicrm/upgrade I get a white screen. When I return to the drupal modules the main civicrm core module is no longer listed. If I run the drupal upgrade script I get an error message that civicrm module is missing ... but I can see the module loaded on the server, with all it's files, in the correct location.
I shouldn't have to uninstall the module because I'm upgrading. I disabled all of the civi helper modules, but made sure to leave the main civicrm module enabled, but I still get the missing module message.
Any help would be greatly appreciated.