Unable to install package. Lock file has not changed, Skipping lock file write - nuget

Question

I am trying to install System.ComponentModel.Annotations through VS 2017 package manager console.
Command:
Install-Package System.ComponentModel.Annotations -Version 4.3.0
Outcome
Restoring packages for
C:\MyTest.csproj...
Installing NuGet package System.ComponentModel.Annotations 4.3.0.
Committing restore... Writing lock file to disk. Path:
C:\MyTest\obj\project.assets.json
Restore completed in 816.43 ms for
C:\MyTest.csproj.
Restoring packages for
C:\MyTest.csproj...
Committing restore... Lock file has not changed. Skipping lock file
write. Path:
C:\MyTest\obj\project.assets.json
Restore completed in 2.03 sec for
C:\MyTest.csproj.
Executing nuget actions took 4.12 sec Time Elapsed: 00:00:05.2258592
Note:
I am using .NETCoreApp1.1 framework.

Answer 1

Unable to install package. Lock file has not changed, Skipping lock file write
I also got the same outcome in the output windows when I restore/update that package, but I found that package was already installed to the project after checking the project Dependencies and project file(.csproj). And the outcome did not tell the installation failed, just prompting skip lock file write:
Restoring packages for C:\MyTest.csproj... Committing restore... Lock file has not changed. Skipping lock file write.
So this message comes only if that package was already installed to the project. When you got that log, you should double check the project reference, make sure if the package already installed.

Answer 2

One should also check if there is a Directory.Build.targets file in some parent directory of the project that defines the version of the package. If this is the case (I had this problem), VS will ignore the version you install and will keep the version defined in the file, so you have to update the version there.