A solution to "An unexpected error has occurred" in WSS v3

Debugging SharePoint can be problematic at times, it does like to hide debugging information from you. The bain of my life recently has been “An unexpected error has occurred” with nothing written to log files, trace or the event log.

Normally I can debug the problem with a little commenting & narrowing down of the problem, but today I have managed to get rid of that error screen completely.

The solution is to change a single entry in web.config, by modifying the line…

<SafeMode MaxControls=“200“ CallStack=“false“…

to…

<SafeMode MaxControls=“200“ CallStack=“true“…

You will also need to set custom errors to 'Off' .

<customErrors mode=“Off“/>

You will no longer see the “An unexpected error has occurred” error page and instead you get a lovely ’standard ASP.Net error page’ with the stack trace and everything…development has got that little bit easier!!