Can't Update or Uninstall NuGet Package Manager in VS2012 - visual-studio

Question

I am unable to update or uninstall the NuGet Package Manager for Visual Studio 2012. I've looked around to several solutions, but have not found one that works.
Running Visual Studio 2012 as the administrator...
Attempting to update the NuGet Package Manager fails, and I get this error dialog with the following at the end of the log:
2/5/2013 10:38:09 AM - Beginning to install extension to Microsoft Visual Studio Ultimate 2012...
2/5/2013 10:38:09 AM - Upgrading 'NuGet Package Manager', version 2.0.30625.9003 to version 2.2.31210.9045.
2/5/2013 10:38:10 AM - Install Error : System.IO.IOException: The process cannot access the file because it is being used by another process.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.__Error.WinIOError()
at System.IO.File.InternalMove(String sourceFileName, String destFileName, Boolean checkHost)
at Microsoft.VisualStudio.ExtensionManager.ExtensionManagerService.AtomicallyDeleteFiles(IEnumerable1 filePaths, Boolean justMarkForDeletion)
at Microsoft.VisualStudio.ExtensionManager.ExtensionManagerService.DeleteDiscoverableFiles(IInstalledExtension extension)
at Microsoft.VisualStudio.ExtensionManager.ExtensionManagerService.UninstallInternal(IInstalledExtension extension, Boolean forceDelete)
at Microsoft.VisualStudio.ExtensionManager.ExtensionManagerService.CommitInstalledAndUninstalledExtensions(IEnumerable1 installedExtensions, IEnumerable1 uninstalledExtensions, IEnumerable1 packComponentChanges)
at Microsoft.VisualStudio.ExtensionManager.ExtensionManagerService.BeginInstall(IInstallableExtension installableExtension, Boolean perMachine, AsyncOperation asyncOp)
at Microsoft.VisualStudio.ExtensionManager.ExtensionManagerService.InstallWorker(IInstallableExtension extension, Boolean perMachine, AsyncOperation asyncOp)
Followed by a popup telling me:
The process cannon access the file because it is being used by another process.
When I attempt to uninstall the extension first (per some solutions) I receive the same pop-up message as above, telling me the process is being used!
Steps I've made in my attempts to get this working:
I've restarted VS2012 multiple times, with and without projects loaded.
I've rebooted the computer several times and started nothing other then VS2012.
I've downloaded the NuGet installer from the web and tried to install it w/o starting VS2012 (first thing after reboot).
For step #3, I receive the same series of dialogs/errors as when attempting to update inside Visual Studio 2012.
I can't get the latest version, no matter what I try! Does anyone have another trick?
I've also noticed that NuGet is just plain not working right now. Neither the "Package Manager Console" or the "Package Manager Settings" do anything.

Answer 1

Source:
http://www.paraesthesia.com/archive/2013/07/30/upgrading-nuget-the-process-cannot-access-the-file-because-it.aspx
This is what helped me:
Close all instances of Visual Studio.
Go to your global Visual Studio extensions folder. NuGet doesn’t
install in your per-user folder; instead, you’ll see it in Program
Files. Something like: C:\Program Files (x86)\Microsoft Visual
Studio 11.0\Common7\IDE\Extensions
Look in that folder. You will see a lot of randomly named folders
like “sdjfksiov.djd” and so on. Most (if not all) of those are
NuGet. You’ll want to be aware of which ones are NuGet and which
ones aren’t, particularly if you have other extensions installed.
(You can tell if it's NuGet because it'll have a bunch of
NuGet.*.dll files in there. If you don't see NuGet stuff in there,
you'll want to keep it.)
Rename that Extensions folder to something like: C:\Program Files
(x86)\Microsoft Visual Studio 11.0\Common7\IDE\Extensions_RENAMED
Download NuGet directly from the Visual Studio extension gallery.
Execute the downloaded NuGet.Tools.vsix file you just downloaded.
Don’t do it through Visual Studio. Just double-click the .vsix file
to install it.
NuGet should successfully install. As part of that install, it will
create the Extensions folder again, so you will once again see
C:\Program Files (x86)\Microsoft Visual Studio
11.0\Common7\IDE\Extensions
Open up your renamed extensions folder and move all of the non-NuGet
extensions into the new Extensions folder.
Now open Visual Studio. You should see the new version of NuGet
installed and working.
You can delete that renamed Extensions folder once you’ve verified
everything is working.
Download VSIX and right click unblock the file and install again

Answer 2

I'm using VS2010, I ended up fixing this problem by uninstalling NuGet Package Manager via the "Add Remove Programs", and then deleting this directory:
C:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\Extensions\Microsoft Corporation\Nuget Package Manager
I could then run the NuGet.Tools.vsix thing ok.

Answer 3

I have VS 2013 Pro installed. What solved this problem for me was to restart into safe mode and re-install NuGet there.
You may also want to look into Adam D's post in the link below (the add-in was blocked by anti-malware software):
Can't Update or Uninstall NuGet Package Manager in VS2012

Answer 4

I found a solution for this issue at -
https://kc.mcafee.com/corporate/index?page=content&id=KB85636&snspd-1015&locale=en_GB&viewlocale=en_GB
Cause:
The Microsoft Visual Studio (VS) process devenv.exe must be excluded in the EEFF/FRP process exclusion registry key.
Solution:
Users with this issue must contact Intel Security Technical Support and quote this article number for assistance with adding the devenv.exe process to the correct EEFF/FRP process exclusion registry key.