I also encountered the error 26105 during the installation of RC1. I have been through all the forum entries [http://forums.microsoft.com/MSDN/ShowPost.aspx PostID=20753&SiteID=1] there seems to be so many varying suggestions I'm unsure which one to try.
It reaches the same point everytime in the logs:
MSI (s) (E4:78) [15:58:24:437]: Invoking remote custom action. DLL: C:\WINDOWS\Installer\MSI40.tmp, Entrypoint: WriteMetabaseChanges
WriteMetabaseChanges: failed to open root key, retrying 0 time(s)...
WriteMetabaseChanges: Error 0x80110414: failed to create web application: /LM/W3SVC/3/Root
This is what's in the event log:
Product: Microsoft Visual Studio 2005 Team Foundation Server - ENU -- The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 26105. The arguments are: -2146368492, /LM/W3SVC/3/Root,
What I want to know is there an actual definition of what the error 26105 is about or what it usually indicates, I just find from reading all the possible solutions a lot of them seem unrelated. I don't want to waste time implementing a solution when I don't have that problem.
If anyone has any suggestions they will be greatly appreciated.
Thanks
Michelle

Error 26105
drougnor
Hi David,
Thanks for the explanation. I found the following article relating to the 0x80110414 error:
http://support.microsoft.com/default.aspx scid=kb;EN-US;297989
I believe the problem I was experiencing was because the IWAM users on my server were not what the Team Foundation Server setup was expecting, that is the IWAM usersnames were different to the server name.
I have since today started from scratch creating a virutal server with windows 2003 server SE then applied SP1 then enabled IIS which I think has rectified the IWAM user not being defualtly named the same as the server. And the installation of VSTFS has been successful wooo hooo that has only taken me 8 working days!
Thanks again for your help.
Michelle
Mangun
Error 26105 indicates a failure to create the IIS web application; specific info about the failure can be found in the Error code (0x80110414 in this case).
The failure code, 0x80110414, is COMADMIN_E_USERPASSWDNOTVALID, which indicates that either the user name or its password is incorrect.
This could be due to an earlier failure, can you provide the log files (called VSMSI* in the %temp% folder)
LanceDelano
I got this same error. It turns out that the DTC service was disabled. After starting it, the install worked fine.
DrunkenProgrammer