Debugging 'Unknown Error Occurred' in SharePoint v3

SharePoint v3 developers often face Unknown error occurred message. Inspect web page source to get more details for debugging.

So… all you SharePoint v3 developers out there (WSS v3 / MOSS 2007)… don’t you just love when you run into that dreaded SharePoint error “Unknown error occurred” message on the generic yellowish & blue page? It’s about as effective as the “Service Engine Soon” light on your car dashboard. Of course, sometimes they get a bit more detailed, but you still get stuck without enough info.

One thing I do on all my development SharePoint sites is to pop open the web.config and make two tweaks so I get the familiar ASP.NET yellow screen of death (YSOD) with the true exception and underlying call stack:

  • Turn the call stack on by searching for and change it to CallStack=“true”.
  • Turn off the SharePoint error pages by turning off custom error pages: change to mode=“Off”.

Shane posted about this a few weeks back. After a few questions were posted about this, I figured I’d repost it here as well.

Andrew Connell
Developer & Chief Course Artisan, Voitanos LLC. | Microsoft MVP
Written by Andrew Connell

Andrew Connell is a web & cloud developer with a focus on Microsoft Azure & Microsoft 365. He’s received Microsoft’s MVP award every year since 2005 and has helped thousands of developers through the various courses he’s authored & taught. Andrew’s the founder of Voitanos and is dedicated to helping you be the best Microsoft 365 web & cloud developer. He lives with his wife & two kids in Florida.

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