What problems does leaving debug=true cause
Every ASP.Net developer knows about this setting, or at least should. But what happens when you forget about this setting and simply install your web application in a production environment.
At Tess's MSDN blog, you will find an article explaining why you should set Debug=False on production servers. There's also a link to Scott Guthrie's weblog which describes the same subject. Both mention the deployment retail setting, which is new in ASP.Net 2.0. It will tell IIS to ignore the Debug=true setting for production servers, simply by placing the following in the machine.config:
<configuration>
<system.web>
<deployment retail=”true”/>
</system.web>
</configuration>
Using this setting, IIS will simply ignore the debug= setting. So you will you never forget to change it when you move your new web application to the production server.