If nothing changed as far as the install goes (i.e. nothing across the whole site) and updating the permalinks did not correct the issue then it is somewhat puzzling. It would probably be worth checking the php error logs and also bringing this up with your hosting support – at least this would be my next move.

Worth mentioning that you should also perhaps upgrade your WP to 3.4.2 which was released on the 6th September primarily due to a security vulnerability discovered in multi-site installs. I am not suggesting this to be the cause as I am not even sure what the alert was about but always best to be safe.

Thanks, the php error logs indicate nothing unusual and our server manager agrees the issue is plugin/wordpress related.

I was planning to update WP and SPF today, but was leery of upgrading either until this issue was resolved for fear of making matters worse.

I’ve ruled out any plugin conflicts and discovered there is clearly something wonky going on with the page permalink or slug. For instance, when clicking the Members button on the Forums page I am redirected to our network directory page at /members instead of /forums/members. 

Since I’ve already tried updating permalinks from both the WP and SPF admin options, is there somewhere in the db I can investigate further?

At this point would you recommend updating both WP and SPF?

Technically it sounds like the WP rewrite-rules record (held in the WP options table) is missing the forum rules or has become corrupted in some other way. These rules records are what WP uses to determine the correct page to load for any requested url.

When you first install SP the forum rules are added to the overall rules ‘pot’. These should also be flushed when the update forum permalink task is run or – indeed – the update WP permalink.

I do recall quite a while back there was another plugin creating rewrite rules that had a habit of trashing other plugin’s rules but it was a long time ago and I have come across nothing recently to suggest anything does.

I would, in the first instance, recommend your WP gets updated but then I believe that any security patch should be installed quickly. You might want to hold off on SP until you have fathomed the 404s however.

What is your server manager basing this opinion on?

All is good now. The issue ended up being a corrupted options table. Thanks for the hint!

Good news but curious. If badly corrupted I would have expected other manifestations…