The reference assemblies for framework .NETCore, Version=v5.0 were not found

Question

I have a UWP project that was created using Visual Studio 2017. It builds fine on this machine (machine 1).

However, when I copy the project over to a machine (machine 2) where I only have the Visual Studio 2017 Build Tools installed, and attempt to build it using MSBuild, I get the following error:

C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets
(1126,5): error MSB3644: The reference assemblies for framework ".NETCore,Version=v5.0" were not found. To resolve this
, install the SDK or Targeting Pack for this framework version or retarget your application to a version of the framewo
rk for which you have the SDK or Targeting Pack installed. Note that assemblies will be resolved from the Global Assemb
ly Cache (GAC) and will be used in place of reference assemblies. Therefore your assembly may not be correctly targeted
 for the framework you intend. [<path_to_my_UWP_project>\UWP.csproj]

I suspect the need for .NetCore v5.0 arises from this line in my UWP.csproj file:

< PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.0.1" />

I do a nuget restore before I build on machine 2, and I can see that microsoft.netcore.universalwindowsplatform successfully gets restored under < C_Users_me >/.nuget/packages, and so does microsoft.netcore.

On machine 1 however, only microsoft.netcore.universalwindowsplatform gets restored but it still builds fine via Visual Studio.

Question: Why am I getting this error and how do I fix the problem?

It is not so obvious to me that cobbling together everything you need to build UWP apps is practical or possible. They do march to a different drummer. The dedicated MSDN page that talks about setting up automated builds is here. — Hans Passant
So your advice is to use the pre-configured UWP build step on VSTS? — Ash
When you use the documented procedure you'll have a much easier time finding help. Assuming you would need any, expectation is that you don't. — Hans Passant
Perhaps (not convinced it won't present its own set of problems though). But I prefer to use my own custom build step as the pre-configured one gives me about 1% of the functionality I need. What surprises me though is that off the three mobile platforms (iOS, Android, UWP), MSBuild struggles to build the one that you'd expect to be the easiest...considering they are both from the same company. — Ash

Leo Liu-MSFT Leo Liu-MSFT · Accepted Answer · 2018-03-14T07:50:57

The reference assemblies for framework .NETCore, Version=v5.0 were not found

According to the error log, it seems you are missing the .NET framework SDK (. NET core, v5.0) on your machine 2. You can check the it from following directory:

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETCore\v5.0

To install it, make sure you are install following individual components:

If you still have that error, please try to copy the directory C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETCore\v5.0 from machine 1 to machine 2.

Hope this helps.

The reference assemblies for framework .NETCore, Version=v5.0 were not found

6 Answers