When check in the project to the TFS or just connect to it an exception is thrown in the application log: 

 Outer Exception Type: System.ArgumentException
     Message: The array must contain at least one element.
          Parameter name: paths
     HRESULT: 0x80070057 (Official ID (if app.) = E_INVALIDARG, Error Bit = FAILED, Facility = FACILITY_WIN32, Code = ERROR_INVALID_PARAMETER)
     Call Stack:
          at Microsoft.TeamFoundation.Common.TFCommonUtil.CheckArrayForNullOrEmpty(Object[] array, String arrayName)
          at Microsoft.TeamFoundation.VersionControl.Client.Workspace.PendAdd(String[] paths, Boolean isRecursive, String fileType, LockLevel lockLevel, Boolean treatMissingItemsAsFiles, Boolean silent, Boolean applyLocalItemExclusions)
          at Microsoft.TeamFoundation.VersionControl.Client.Workspace.PendAdd(String[] paths)
          at ArtOfTest.Common.TFSClient.TFSServer.AddFiles(IRepositoryInfo repository, String[] files)
          at ArtOfTest.WebAii.Design.ProjectModel.Providers.SourceControl.SourceControlProviderBase.AddItems(String[] filePaths)

Steps to reproduce and customer project are in the internal description.