TF400618: The reporting type of field 'Microsoft.VSTS.Common.StateChangeDate' in work item type 'Feature' conflicts with the reporting type of the existing field
After upgrading to TFS 2013, the first thing you need to do is running the ‘Configure Features’ wizard. This will enable some of the new features in TFS 2013 for your existing Team Projects.
Before the configuration takes places, TFS will verify if is able to automatically update your Team Project. For one customer, we were out of luck and the verification failed with the following error message:
[Error] TF400618: The reporting type of field 'Microsoft.VSTS.Common.StateChangeDate' in work item type 'Feature' conflicts with the reporting type of the existing field
We took a look at the ‘Resolve Errors’ MSDN page and found that we could fix the issue by changing the Field definition of the stated item by using witadmin changefield.