Hi, I'm having this problem and I didnt find any answers on the web. I have a content type named "Document X" with the original "Document" as parent. When I create a new content type named "Document X 2" with the parent "Document X", I get the error "A duplicate content type 'Document X 2' was found"... I checked the ULS and the error isn't reported there. I can create new content type from any other content type (out of the box or others I created) but I cant create new one from that "Document X". (And no I dont have any content type named like that.. whatever name I use, I get the same error) Full error is: A duplicate content type "Document X" was found. Troubleshoot issues with Microsoft SharePoint Foundation. Correlation ID: b9d36bb8-1a8e-4ef4-bbd0-fbdf8e70d73b Date and Time: 1/24/2011 3:00:36 PM I know I dont have much info to give here, I just dont know where to look first.. This error is happening on my content type hub site but I use and create content type on this site only. If anyone have any idea that could help me, I would really appreciate it as I lost a few hours on this already and dont know where to look anymore... Thanks a lot, JP Berube