Guys, as promised, this is my second post in same day because I got to resolve one of the very weird and unique case recently. The resolution is of one line but issue is so complex, that if we cannot figure that out, we may end up trying to figure out for rest of our lives :).

So for TFS community benefit and user's respite, here I am again with the following problem and solution.

Symptoms

In case of TFS set up as FQDN(FULL QUALIFIED DOMAIN NAME)even after checking all the permission in TFS, if we are not able to create, build, merge the projects or do any operations in TFS and get authentication failure error messages like below:

TF53010: An unexpected condition has occurred in a Team Foundation component. The information contained here should be made available to your site administrative staff.
Technical Information (for the administrative staff):
Date (UTC): 16/12/2009 14:55:56
Machine: PORWA200
Application Domain: /LM/W3SVC/3/Root/Build-4-129054476476531826
Assembly: Microsoft.TeamFoundation.Build.Common, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a; v2.0.50727
Process Details:
  Process Name: w3wp
  Process Id: 988
  Thread Id: 4516
  Account name: Domain\username

Detailed Message: TF42056: The build service could not connect to the Team Foundation Server: TF30063: You are not authorized to access http://FQDN:8080/.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. 

 Let me know when you are ready to restart your server then we can do a LM and add that registry key.

Cause

These issues happen due to loopback. Basically when any authentication calls goes within the server which mean the authentication request is coming from server itself and not from client and the setup is FQDN, server tried to reject those request.

By default, loopback check functionality is turned on in Windows Server 2003 SP1, and the value of the DisableLoopbackCheck registry entry is set to 0 (zero).

Note The loopback check functionality is stored in the following registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\DisableLoopbackCheck

 

Resolution

So if we disable the loopback then it will accept the request and everything in Team Foundation server(be it project creation, build or branching and merging) will work fine.

 To set the DisableLoopbackCheck registry entry to 1, follow these steps on the TFS Server Machine:

  1. Click Start, click Run, type regedit, and then click OK.
  2. Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
  3. Right-click Lsa, point to New, and then click DWORD Value.
  4. Type DisableLoopbackCheck, and then press ENTER.
  5. Right-click DisableLoopbackCheck, and then click Modify.
  6. In the Value data box, type 1, and then click OK.
  7. Exit Registry Editor.
  8. Restart the computer.

Note You must restart the server for this change to take effect.

 Hope it will make lives of  TFS Admins lot easier, hunky dory and all well....Till next post Dasvidaniyaa.......

Nitish