Hello leonjb, do you have access to your server? If you all you have to do is go to your server root directory and then to your plugin directory and delete all the entries for your plugin cache.
Before you begin just in case something might go wrong, create a backup.
The path will be something like:
server path/your website/wp-content/cache/hyper-cache….delete all cache files in this directory.
You might also want to disable or delete the plugin after you have deleted all the cache….Simpy navigate to the following path…
server path/your website/wp-content/plugins/hyper-cache…..rename the folder to something like old-hyper-cache will disable and stop the cache plugin from running.
This should get your issue resolved.
However there might be other factors that have caused Hyper-cache from working properly after the upgrade to WordPress 3.7.1. Your theme might have issues or you might have a conflict with another plugins. I am running Hyper-cache with WordPress 3.7.1 in all my blogs without any issues.
Let me know if this helps you.
Kind regards
