Recently I started seeing a problem creep into my wordpress installations.
I found that when I tried to save an option selected in the ADMIN panel of my WP site ,the Option did not execute or save. Instead I received a 404 Error telling me the page was not found. After spending a lot of time tracking this down I found the problem was coming from a .HTACCESS file in the WP-ADMIN sub-directory blocking the file WP-NAV.PHP.
Upon removing this .HTACCESS file all functionality returned to Normal. It appears that the offending code was places by BulletProof Security Version 47.8 however I can not be certain of that.
I would really appreciate knowing if this has helped anyone or If any one has any more information on this issue. Please feel free to reach out to me at lee@Leebinder.com