Last week one of my colleagues contacted me about an issue he encountered. When trying to open the navigation settings page (/_layouts/AreaNavigationSettings.aspx), he encountered an "Unknown Error" (don't you just love those nice and clear errors). When opening the default page, the Quick Launch navigation on that page was also displaying errors:
When using the CustomErrors=Off and StackTrace=True options in the web.config, we were able to retrieve a "Object reference not set to an instance of an object" message. In the ULS logs, we found the following errors:
- Unable to retrieve the CachedObject that this ProxySiteMapNode references: /sites/test/sites/183/Pages/testpage.aspx
- PortalSiteMapProvider was unable to fetch children for node at URL: , message: Object reference not set to an instance of an object
The quick launch navigation was changed manually and navigation items were added. Looking a little further, I found that testpage.aspx didn't exist anymore in the Pages library. Probably a user had deleted this page, causing this issue. When I recreated the testpage.aspx, the Quick Launch navigation started working again and the Navigation Settings page didn't show the error anymore.