Yust for everybody who didn't know this...  
  
http://msdn.microsoft.com/windowsvista/support/relnotes/default.aspx

I've just installed the winfx runtime, and now I'm trying to install  
  
the SDK.  
  
It fails during installation saying that the cabinet file: MSI13C.tmp  
  
has an invalid digital signature.  
  
When I view the certificate (right click->digital signatures->details)  
  
it says that the certificate in the signature cannot be verified. If I  
  
look at the certification path it goes back like this:  
  
Windows 32 SDK - the current certificate  
  
Microsoft Windows Redmond  
  
Microsoft Test PCA - and stops here, saying the issuer cannot be  
  
verified  
  
The issuer is Microsoft test root authority.  
  
Where can I get this certificate? Because even if I install the Windows  
  
32 SDK in the trusted publishers, or install the Test PCA certificate  
  
in the trusted root CA, it still says that the signature is invalid.  
  
Perhaps the certificate should be distributed along with the winfx sdk?  
  
How do I make it install? Has anyone succeeded yet?  
  
I am using:Windows XP professional version 2002 service pack 2  
  
Thank you

We are investigating a problem with the WinFX Beta 1 SDK Web install.  We  
  
hope to have it fixed by EOD or earlier.  
  
We apologize for any inconvenience.  
  
--  
  
Lori Pearce  
  
Longhorn SDK Team  
  
"edwin" <edwintorok@gmail.com> wrote in message  
  
news:1122542838.725834.235330@g49g2000cwa.googlegroups.com...

Both the ISO and Web Install of the WinFX SDK should be working fine now.  
  
Lori Pearce [MSFT]  
  
Vista SDK Team  
  
--------------------  
  
<1122542838.725834.235330@g49g2000cwa.googlegroups.com>  
  
"Indigo") Bet  
  
microsoft.public.windows.developer.winfx.indigo:1803