Update to Wordpress 4.9 crashes

Hello, I am trying to update Wordpress since yesterday. The first try took ages and failed, today it crashes completely, both the site and wp-admin area are not available.

I checked your account and these were the error messages I saw:

Warning: require_once(/home/vol8_5/epizy.com/epiz_20814480/htdocs/wp-includes/widgets/class-wp-widget-media-gallery.php): failed to open stream: No such file or directory in /home/vol8_5/epizy.com/epiz_20814480/htdocs/wp-includes/default-widgets.php on line 35

Fatal error: require_once(): Failed opening required '/home/vol8_5/epizy.com/epiz_20814480/htdocs/wp-includes/widgets/class-wp-widget-media-gallery.php' (include_path='.:/usr/share/pear/') in /home/vol8_5/epizy.com/epiz_20814480/htdocs/wp-includes/default-widgets.php on line 35

As far as I can tell, your Wordpress installation was corrupted. An easy way to try and fix this is by downloading a fresh copy of WordPress and uploading it on top of your existing one, overwriting any existing files. That should fix any issues related to missing or corrupted files.

Thank you very much, I will try. My installation was a quite fresh one-click-installation, I do not understand how it could happen.

@Tanja_Kim said:
Thank you very much, I will try. My installation was a quite fresh one-click-installation, I do not understand how it could happen.

A WordPress update (or any update for that matter) can be a big and complicated process and a lot can go wrong during it. Usually it goes right, but sometimes it doesn’t.