Error Installing NuGet 1.8

Question

NuGet 1.8 seems to have some interesting new features. Unfortunately when I attempt to update from within Visual Studio, I get the error:

Value cannot be null.
Parameter name: v1

I figured I would just install it from outside Visual Studio and see if that works better, but the download link I found

http://nuget.codeplex.com/releases

does not list any downloads for "NuGet Visual Studio extension".

How can I update NuGet?

Update

This is on Windows 7 64-bit, Visual Studio Ultimate 2010SP 1, upgrading from recent NuGet version (how do I check version number?) to NuGet 1.8.

Answer 1

Based on the comments, I did the following:

• Closed all instances of Visual Studio
• Started a new instance of Visual Studio as Administrator
• Tools / Extension Manager
• Select NuGet Package Manager
• Click Uninstall (if you're not Administrator, Uninstall is grayed out)
• Restart Visual Studio (still as Administrator)
• Tools / Extension Manager
• Online Gallery
• Install NuGet
• Restarted Visual Studio (this time not as Administrator)
• Resumed work