This is a setting that can be used by developers to tell the store to override its normal security protection mode which prevents the display of error messages to your screen.

Caveat: Outputting errors to the screen can cause some screens or features to not work correctly, especially those which involve being forwarded to another page based on certain criteria or after certain steps are completed.

Caveat: Also, using this option poses a security risk because error messages will disclose path and database information to malicious visitors who attempt rogue behaviors on your store. THUS, THIS SETTING SHOULD ONLY BE USED IN AN OFFLINE DEVELOPMENT ENVIRONMENT. Using it on a live store poses risks, and should only be used for short-term troubleshooting of a problem which can't be solved any other way.

Enabling STRICT_ERROR_REPORTING

To enable STRICT_ERROR_REPORTING, simply use your FTP program to upload a simple file to your store's site like this:
- For storefront problems, put it at: /includes/local/configure.php
- For admin problems, put it at: /name-of-your-admin-folder-here/includes/local/configure.php

Disabling STRICT_ERROR_REPORTING

Simple: When you're done with the tool, simply delete the "local/configure.php" file you uploaded above. (DO NOT delete the main configure.php file; only delete the one you put into the folder named "local"!)

If that doesn't disable it, then that means you've enabled it in another file on your server. You will need to search your entire site for that define statement and remove it. (See the Developer's Toolkit for that.)