Archives: February 27, 2013

TFSJobAgent Error–An item with the same key has already been added

I’ve posted this more as a reminder to myself next time I create TFSJobAgent plugins.

If you ever encounter the error below when adding a new TFSJobAgent plugin:

TF53010: The following error has occurred in a Team Foundation component or extension:
Date (UTC): 2/25/2013 2:04:52 PM
Machine: VSTSR-VM2012RTM
Application Domain: TfsJobAgent.exe
Assembly: Microsoft.TeamFoundation.Framework.Server, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a; v4.0.30319
Service Host:
Process Details:
  Process Name: TFSJobAgent
  Process Id: 8996
  Thread Id: 6656

Detailed Message: There was an error during job agent execution. The operation will be retried. Similar errors in the next five minutes may not be logged.
Exception Message: An item with the same key has already been added. (type ArgumentException)
Exception Stack Trace:    at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at Microsoft.TeamFoundation.Framework.Server.TeamFoundationExtensionUtility.LoadExtensionTypeMap[T](String pluginDirectory)
   at Microsoft.TeamFoundation.Framework.Server.JobApplication.SetupInternal()
   at Microsoft.TeamFoundation.Framework.Server.JobServiceUtil.RetryOperationsUntilSuccessful(RetryOperations operations, Int32& delayOnExceptionSeconds)

The above error was caused by me having more than one copy of my component in the plugins folder

C:\Program Files\Microsoft Team Foundation Server 11.0\Application Tier\TFSJobAgent\plugins

You’re probably wondering how this is possible? I actually had another folder in the plugins folder with a copy of my component. The TFSJobAgent uses reflection to find all components that implement the ITeamFoundationJobExtension interface at runtime this includes all subfolders under the plugins directory.

New Tools for TFS Administrators in TFS 2012

There are some really useful new tools for administrators in TFS 2012, I’ve only just seen this now on Grant Holliday’s blog but you can now do things such as look at the TFS Activity Log and one of the most important ones for me is TFS Job Monitoring.

You can get to all of these from your TFS installation by going to the following link.


For more information visit Grants blog. Enjoy!