VS TFS The work item cannot be saved because at least one field contains a value that is not allowed

You may get this bug:

1. if you have a Build > Process > Advanced > Create Work Item on Failure
2. possibly also if you are checking-in code against work items

This occurs because the account performing the build does not have permission to create/update the work items

To solve this I believe that you

1. Give the account running the build the correct permission, probably in TFS Adminstration Console > Team Project Collections > <your project>
2. Either change the account running the build in TFS Administration Console > Build Configuration