One of my clients has suffered a fatal crash on a new website build for version 5.7.5.12. he was busy moving blocks around and building nested layouts when he got a 502 Invalid response. From that point any attempt to connect to the front end pages results in a 502. We are able to login to the dashboard.
I have spent some time looking at the issue, the previous web developer who built the custom theme also removed all of the default C5 themes so switching to those was not an option. By switching to a slightly older db version, of about 3 days he is able to load and browse the site.My client is currently rebuilding the site in preparation for a go live early next week,
I have managed to download the corrupt database and the website which I am putting onto a dev server to try to fix or understand the issue. Having dumped the database there are no obvious db issues. But we have a very strong feeling that the issue is a corrupt core table or missing record, does anyone know of a database integrity checking script that could be used to validate the core database tables?

Thanks
Martyn