Version: Magento 1.5+
By default, Magento does not show detailed error messages and shows an error log number only. For example,
There has been an error processing your request
Exception printing is disabled by default for security reasons.
Error log record number: 1816309327
Magento is a trademark of Magento Inc. Copyright © 2010 Magento Inc.
Magento does not show verbose error messages by default for security reasons.
Full error details can be found in the /var/report/ directory. Look for a filename that matches the error log record number in the error summary.
To enable verbose errors, rename the following file: /errors/local.xml.sample –> /errors/local.xml