Internal Server Errors – Moving working multi-site install to my localhost

For anyone who stumbles across this, the issue lied within my wp_2_options table (the options for my second site within the multi-site).

Whereas for the most part you can forego the http:// before your localhost domain, in this table you cannot. This was causing issues when attempting to upgrade the network etc.

I hope this helps someone – I knew it would be something ridiculous.