SharePoint 2010 has significantly improved troubleshooting of errors with the introduction of "correlation ids". Those IDs allow for an easier troubleshooting process when looking at SharePoint ULS logs (where they are referenced), but they usually require that you have 1) access to the SharePoint server where the error occurs (which might not be very easy in load-balanced environments) and that 2) you take a snapshot of the ULS log file as soon as the error occurs.
In order to ease the troubleshooting process, we advise you to turn on some settings so that you will see the full stack trace of the error on the page where it occurs. Of course, those settings should be turned back off after troubleshooting was performed.
Here are the instructions to turn on full stack trace error messages (instead of standard "Correlation ID" error messages) in a SharePoint 2010 environment:
- Open the web.config file for your web application's zone on the SharePoint web front end server(s)
- Search for "CallStack" and set the value to true (false is the default value)
- Search for customErrors and set the mode attribute to "Off" (with an uppercase O, this is important)
- Save the web.config file
- If the error occurred on a layouts page (i.e. a page whose Url contains "_layouts"), navigate to the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS folder for SharePoint 2010, the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\TEMPLATE\LAYOUTS folder for SharePoint 2013, or the C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\TEMPLATE\LAYOUTS folder for SharePoint 2016.
- Open the web.config file in that folder and set mode="Off" for the <customErrors> node
- Save the file and navigate to the page where the error occurred. You should now see the full stack trace of the error message
- Last but not least, remember to set those settings back to their original values when you are done troubleshooting your issue!