Website Has Reformatted After Updating to 3.9.1

Make sure you’ve update all plugins and themes too. A quick fix would be to load the backup copy that you had made before the update.

Are you using child themes?
Have you made any changes to wordpress core functions?
Do you get any errors in your webserver log file?

Thank you for your response, much appreciated.

I have updated everything, but have not made any backup copies as it didn’t tell me to – Or does it auto save a backup when you update it?

I have just had a look at child themes but do not understand how this would help?

Your hosting provider should have backups for your site, you can ask them to load a pre-update backup.
This will be only a quick fix (not a solution) since you’ll still have to update wordpress and your site.

I was asking if you are using child themes or not beacase if you are they are build on custom code that might cause issues.
If you are not using any child themes (only default script themes) that would be better as we can reinstall the theme also without loosing any data.