i am trying to install Microsoft.Bcl.Build 1.0.14
nuget returns
Installing \'Microsoft.Bcl.Build 1.0.14\'. Successfully installed \'Microsoft.Bcl.Bu
Check your packages.config
Inside there, check for the packages you are trying to install. Maybe some reference are already there and this avoid that you can install the new ones.
If you find there the references, delete the reference from the packages.config and try to install again the package.
It happened to me sometimes that inside packages.config are some old reference that still left there even after removing the package from the Nuget Package Manager.
If not, you can delete the entire packages.config, then if you have the option to let Nuget download the packages, when you build your solution, the packages will be downloaded again.
I hope this helps