Sharepoint 2010 – how to show error details when debugging
Showing actual error details with the stacktrace is usually a quick change in web.config for any ASP.NET web application. For Sharepoint 2010 a few more steps are required, as there are several web.config files spread around.
In my case, the web.config files to change were:
C:\inetpub\wwwroot\wss\VirtualDirectories\[your_web_app]
Set <customErrors mode=”On”> to Off
Set <SafeMode .. CallStack=”False”> to True
Set <Compilation batch=”False” to True and <Compilation Debug=”False” to True
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS
Set <customErrors mode=”On”> to Off
Ensure <compilation batch=” ”> is Off
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\CONFIG
Set <customErrors mode=”On”> to Off

January 30th, 2012 - 09:34
Saved a lot of frustration , Thanks
April 26th, 2012 - 15:41
The line Ensure <compilation batch=” ”> is Off
Should be: <compilation batch=” ”> is false