NuGet upgrade issue

I have the version of NuGet that comes with MVC3 (1.0), but when I try to upgrade to the latest version (currently 1.4) it failes and I get this in the log file:

>6/27/2011 1:25:08 PM - VSIXInstaller.SignatureMismatchException: The installed version of 'NuGet Package Manager' is signed, but the update version has an invalid signature. Therefore, Extension Manager cannot install the update. at VSIXInstaller.Common.VerifyMatchingExtensionSignatures(IInstalledExtension installedExtension, IInstallableExtension updateExtension) at VSIXInstaller.InstallProgressPage.BeginInstallVSIX(SupportedVSSKU targetAppID)

>6/27/2011 1:25:08 PM - Install Error : VSIXInstaller.SignatureMismatchException: The installed version of 'NuGet Package Manager' is signed, but the update version has an invalid signature. Therefore, Extension Manager cannot install the update. at VSIXInstaller.Common.VerifyMatchingExtensionSignatures(IInstalledExtension installedExtension, IInstallableExtension updateExtension) at VSIXInstaller.InstallProgressPage.BeginInstallVSIX(SupportedVSSKU targetAppID)

>6/27/2011 1:26:27 PM - VSIXInstaller.SignatureMismatchException: The installed version of 'NuGet Package Manager' is signed, but the update version has an invalid signature. Therefore, Extension Manager cannot install the update. at VSIXInstaller.Common.VerifyMatchingExtensionSignatures(IInstalledExtension installedExtension, IInstallableExtension updateExtension) at VSIXInstaller.InstallProgressPage.BeginInstallVSIX(SupportedVSSKU targetAppID)

I even tried uninstalling NuGet (via Add or Remove Programs) and installing 1.4 manually, but I inexplicably get the same message. Any idea what I'm doing wrong?

1. Close all visual studio 2010 instances.
2. Open visual studio again as administrator
3. Go to "Tools" > "Extension Manager"
4. Uninstall NuGet
5. Install NuGet again.

if you are not able to uninstall it go to:

C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\Extensions\Microsoft Corporation\NuGet Package Manager

and remove this folder. deleting this is at your own risk!

This is documented on our Known Issues page: http://docs.nuget.org/docs/reference/known-issues

There's two reasons why you might run into this issue. You've installed an unsigned or wrongly signed version of NuGet. For example, if you grab a build off of our continuous integration server (http://ci.nuget.org/) or if you installed one of our previous CodePlex releases.

There's another issue affecting some users of Windows XP or Windows 2003 where it appears the certificate authority on the machines are incorrectly reporting the certificate as not valid. We're still investigating this issue.

From NuGet page on VS Gallery website:

"Review current release notes/known issues on the NuGet Docs site, including details and solution for about a common upgrade failure (Visual Studio 2010 SP1 Hotfix available)"

I uninstalled via Tools | Extension Manager, then was able to install successfully. If I had read Hanselman's post a little more carefully, I would have realized 1.0 doesn't play nice.

If you run as admin, and uninstall, and cannot get to the online archive.... you can still install by downloading the vsix file https://docs.nuget.org/consume/installing-nuget