One or more packages could not be completely uninstalled

One or more packages could not be completely uninstalled

I have an ASP.NET MVC 4 application. I used NuGet to update all of the
NuGet packages that were installed when I created the application. One of
the packages was Microsoft.Bcl.Build.
After updating these, NuGet displayed the following message at the bottom
of its window:
I have since restarted Visual Studio several times, but the message still
exists. When I checked the installed packages, it did appear that the
updated version (1.0.8) of the package was present.
How can I fix this?