I agree that the BIN folder is not relevant here. But the .dll References in the Solution is the wrong one. I found the following message on Stackoverflow

In my case it was a tfs issue, since tfs exclude binaries, so the Nugget PM find the nugget installed and don't update the library If you have similar issue :
 •Go to source control
 •Navigate to the ..\packages\Microsoft.Web.Optimization 
•Add lib folder (uncheck the exclude binary extensions)
 •Update your solution and add the dll reference from the path
 
NB : the package folder is in the same level of yousolution.sln file

But I don't understand what the author means by "Go to source control". If you know how to get to Source Control, please let me know.

Thanks.


>NuGet may not update the bin folder (remember, there are multiple bin folders -- Debug, Release, etc). Check the properties of the DLL from inside VS. Copy Local should be true. When you build, it will copy the DLL to the appropriate bin folder.
>
>>Strange that after I - supposedly - updates the Microsoft.AspNet.Web.Optimization.WebForms, the version in Properties still shows 1.0.0.0.
>>
>>When I look at the BIN folder of my solution the Microsoft.Asp.Net.Web.Optimization.WebForms.dlll still of older date (10/13/2013).
>>But the folder MySolution\Packages\ has new folders with the new version number. Do I need to 'manually' move the file from Packages to BIN?
>>
>>UPDATE. The current .dll points to this folder:
>> D:\VS2012\WebProjects\MySolution\packages\Microsoft.AspNet.Web.Optimization.WebForms.1.0.0\lib\net45\Microsoft.AspNet.Web.Optimization.WebForms.dll
>>
>>But the NuGet created folder:
>>..packages\Microsoft.AspNet.Web.Optimization.1.1.2.lib.net40 where the more up-to-date DLL resides.
>>
>>I thought that NuGet would update the solution but it didn't