We recently had a client whose CMS stopped saving data. We knew we hadn’t touched the code on it in at least a year, so it was a very strange situation. After poking around, googling incessantly and debugging a ton, we discovered that another developer who had been working on SEO modifications for them had created a .htaccess file that was wiping out all POST data sent to a index.php file — ANY index.php file. Our app was written in an older version of the Fusebox 3.0 framework for PHP and as such, everything is channeled through the index.php file in the CMS directory.
The fix? Adding a new .htaccess file into the CMS directory that turns off the Rewrite Engine did the trick.