We received the below Error in Site Manager page in Some sites. Here is the RCA and resolution:
Root cause: We have installed some third party products, which internally created its Templates(List template, Document Library template, etc) ,we removed those third party products and the objects created with their template are broken now!
When we open the site manager it tries to get the custom list template, its icon, etc. and if its broken sitemanager.aspx throws the error.
Say for e.g. we have installed the Bamboo solutions video product, created some video libraries, and then uninstalled the product. Now ALL the video libraries are broken because: we’ve uninstalled the product, it’s wiped out along with its templates.
So the solution Is: Either to delete the objects(We have to use either stsadm: stsadm -o forcedeletelist -url http://youdomain/yourListNameThatHasAPloblem/ or SPD to delete the broken objects.) created with a custom template or use the utility: http://splistinstancefix.codeplex.com, again this tool has some limitation, we can’t simply re-associate the All the broken lists with another template.
I’ve tested the both the scenario’s. After deleting a broken object, sitemanager.aspx ran without any error.