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