Scenario: You are working in a site collection where the root site was instantiated from a web template. You have then created subsites which you wish to save as a web template. Upon doing so, you receive an error.
Error exporting the list named “Announcements” at the URL: Lists/Announcements
If you rename the list and try to save as a template again it will just give the same error with a different list, in alphabetical order. When you look at the correlation ID you see:
SPSolutionExporter: System.NullReferenceException: Object reference not set to
an instance of an object.
This is the one of the first lines in the log for your correlation ID. When you look at the content types for your subsite, you see some of your custom content types but none of the defaults. When looking at the root web for the site collection you see the same.
Run the SharePoint 2010 Management Shell as Administrator. Run the following command to disable the default content type feature:
Disable-SPFeature –Identity ctypes –url http://SiteCollection
Then enable the content type feature:
Enable-SPFeature –Identity ctypes –url http://SiteCollection
If you look at your content types, they should now all be there. Try saving the subsite as a template again, it should succeed.