Categories disappeared?!

edit 2, that’s tested easily be deactivating that plugin.
When you have a peek into your database, are the categories and tags tables filled like they should be?

Yes, the wp-terms table is still full with all my tags and categories. However, in my wp-posts table, all my posts are listed as having no categories.

And I did try deactivating it, didn’t work. I even just tried to download a new beta version of the plugin that the author updated for 2.7, still no go.

Strange. Perhaps you have another conflicting plugin?

I’ve just tried disabling every single plugin and still no go. I wonder if generating a google sitemap using an outdated version of the plugin would have wrecked that much havoc on my SQL database.

this is getting VERY VERY FRUSTRATING.

I can’t imagine that it wrecked your database, like you said, it looks the way it should. Perhaps the plugin edited some files that now malfunction. My next test would be reuploading WP files (first those in the root and then folder by folder (admin first) until it works).
Unless somebody has a better idea of course.

Is it possible for me to “reinstall” wordpress and have it link back to the same database without me losing any posts?

EDIT: I just hit reinstall wordpress automatically in my dashboard and absolutely nothing changed. WHAT THE HELL IS HAPPENING.

I just checked, seems like all the connections in my SQL database (ie. linking of posts to tags and categories) are exactly the way they should be, but nothing’s showing up in my dashboard.

Oh one more thing, when I tried adding a random new category, it immediately pops up as the only category in the list through AJAX. However, the moment I refresh the page, it’s gone again..

It looks like the admin side of your WP is messed up. I don’t know what your automatic installation function does, but I’d go for ‘manual mode’ (using FTP).
And just curious, but do the categories and tags work on the blog itself?

Nope, tags and categories do not work on the blog. However, when I click on the tags section in my dashboard, it lists all the tags just fine. But for some reason the posts aren’t linked to the tags. In my blog, under the categories section it also says “no categories”

Wow, thanks so much Gangleri, I did what you said and reinstalled my wordpress through ftp and now everything’s working perfectly again. Haha, thanks a lot, I would never have thought of doing that myself.

To anyone who has this problem, try reinstalling your wordpress through ftp, just overwrite all the files, you won’t have to do any configuration stuff all over again

fortunate, i had to replace my taxonomy table with a back up to fix this problem.. appears that missing/corrupted tables, bad plugins, and bad installation files all can cause this problem.

I had the problem described here and in more depth in this post, all I did to solve this problem was restart my VPS (reboot the server), but this was after I had gone through each plugin one by one and re-uploaded WP which had no affect, it was a mission of trial and error. The problem appeared for no reason inflicted by myself, so it may have been related to something on the server being updated or maintained and would explain why the same problem occurred on separate blogs hosted on the same server. The restart solved it.

– Quote from here.