[betterthanyours]

Thanks Lynne for your assistance.

I managed to resolve the issue, it was related to vaultwiki. I'll explain for the benefit of someone running into in the future.

Some six months ago, I installed vaultwiki, I didn't end up using it so I tried to uninstall it. When I pressed the uninstall button, it spat out an error. Throughout those six months, I kept getting db errors relating to it. I didnt keep a record of those or take any notice because it wasn't affecting the forum function but it was still in the plugin list and would generate the same error each time I tried to remove it from the list by clicking uninstall. Once I upgraded to 4.2 it totally broke the forum and was no longer listed in the plugin menu.

I believe it didn't uninstall correctly and vb thought the vaultwiki was still installed. It used to show up in the previous install before upgrade but hasn't been since upgrade.

I had a look in plugin manager and manually disabled ALL under "ces_nwsp_spec" which resolved the issue.