SharePoint–Invalid List Template

Get an “Invalid list template” when trying to access a SharePoint site.

I managed to resolve the issue by adding ?contents=1 after the default.aspx.

For example: http:///myspsite.deinfotech.net/apdata/default.aspx?contents=1

This will open up the “Web Part Page Maintenance” page. I am then able to select the invalid list and close it. After closing the invalid list, I am able to access the SharePoint site again.