I'm experiencing the following problem: I have a local copy of my WordPress site and a corresponding live version on my server.

I added some new blog categories on my local version and created some new blog posts.

Then, I made a database dump and a copy of the document root files from the local version. After I did that, I made a backup of the old document root files on my server and deleted them. Afterwards I've copied the local copies of the database dump and php files on my server, inserted the database dump, placed the local PHP files on the servers document root and checked if everything is alright with wp-config.php.

And now guess what? The posts and categories structures where totally messed up. Old posts had the new categories assign (ones, which were created on the local system) and the new posts were only drafts and had no content and no categories assigned.

What my expectation was: As I have removed all "old" server files (database files and document root) and inserted both a fresh database copy and a fresh document root copy, I expected that everything will look like my local copy of WordPress. Also a few month ago I experienced the same problem when I changed some stuff in my navigation menu locally and updated the files on the server (including the database) with fresh copies from the local system - the menu on the server was then messed up.

This means to me that WordPress somehow remembers some old state, which is totally weird to me as I can not image how it is doing that as both database and PHP files are exactly the same as on my local system.

Does anyone has an idea of what is happening here?