Exception:

TF400917: The current configuration is not valid for this feature. This feature cannot be used until you correct the configuration

Explanation:

After adding a initial state New to  Bug work item workflow, the backlog and the task board showed the error:

TF400917: The current configuration is not valid for this feature. This feature cannot be used until you correct the configuration

Solution:

1. Export team project's CommonConfiguration.xml

witadmin exportcommonprocessconfig /collection:<Collection URL> /p:<Team Project Name> /f:<CommonConfiguration.xml>

2. Add the new state to CommonConfiguration.xml's BugCategory

  <BugWorkItems category="Microsoft.BugCategory">

    <States>

      <State type="Proposed" value="New" />

      <State type="InProgress" value="Active" />

      <State type="Complete" value="Closed" />

      <State type="Resolved" value="Resolved" />

    </States>

  </BugWorkItems>

3. Import the updated CommonConfiguration.xml to team project

witadmin Importcommonprocessconfig /collection:<Collection URL> /p:<Team Project Name> /f:<CommonConfiguration.xml>

Explanation:

System field named "Tags" column was added on the product backlog Workitem Type.

<ProductBacklog>
<Columns>
<Column refname="System.Title" width="400" />
<Column refname="System.State" width="100" />
<Column refname="Microsoft.VSTS.Scheduling.StoryPoints" width="50" />
<Column refname="Microsoft.VSTS.CMMI.RequirementType" width="50" />
<Column refname="System.IterationPath" width="200" />
<Column refname="System.Tags" width="200" />
</Columns>

Solution:

Open Team project Web Access page

The project created using Scrum process template will have “Product Backlog Item” and “Bug” work items as Product Backlog Type

 The project created using Agile process template will have “User Story” work items as Product Backlog Type 

The project created using CMMI process template  will have  “Requirement” work items as Product Backlog  Type 

Explanation:

• The Work item with large amount of data in the custom HTML fields fails to open after migration.
• The error may occur for the build logs with large amount of data as well.

Workaround:

Try to modify web.config in \Program Files\Microsoft Team Foundation Server 11.0\Application Tier\Web Services to adjust the size.
The default length is 20MB, so try a larger value than that. The value below is for 50MB. Experimentation may be necessary to find the best value.

<appSettings>
<add key="maxJsonLength" value="52428800" />
</appSettings>

Value is specified in byte