Drupal: "The directory is not writable"

Question

I recently upgraded my Drupal core from 6.15 to 6.26. In the update process, I was asked to make a backup of all my files, then delete the entire Drupal installation from my server, and rebuild it using the supplied files. I then copied all relevant back-up files back to the server from my local machine. The problem I'm having now is that I get a "The directory is not writable" notification whenever I do any sort of action as an admin. Initially, I was getting the error that "sites/default/files" was not writable, but I fixed that, and I changed the permissions on every file in the installation to 755. Why am I getting this error, and how can I fix it?

Answer 1

Although permissions may be set to 755, most likely the directory ownership is set to the wrong user.