Answered Upgrade to 2.6.1

I'm sorry you got hacked.

Is it possible that it was an Evolution site? There's no direct upgrade path to Revolution.

Did you upload the new files individually with FTP? That often results in missing or corrupted files.

Another possibility is that some of the new files failed to overwrite the old ones (especially if you used FTP), so you're running a new setup on old core files.

FYI, upgrading MODX by itself will help protect MODX from future hacks, but usually won't do anything to help with a site that's already been hacked since it's not the MODX core files that have been altered. For example, the user could have placed a file on your site (say under the assets or cache directory) with any name and still execute that file by entering it's URL in a browser no matter how many upgrades you perform.

It's important to find the entry points the hacker is using (sometimes there's more than one). For starters, look for any users that don't belong and any plugins or snippets you didn't install. A plugin called something like core services is a common hacker entry point. Also look inside the index.php or any index.html files on the site for suspicious code.