Building Project for Hololens with C# Project selected and Playmaker 1.8.3 installed with the uGui ProxyFull unity package also installed willl cause Visual Studio build to fail. There was a minor edit to one of the Playmaker uGui scripts that was suggested by the Playmaker developer to resolve a compile issue in Unity. I have attached screenshots to show this. I have been troubleshooting this issue with the Playmaker Developers and with a Unity Representative on the Unity Forums who requested I submit this issue.

Notes:
Issue repro's in:
5.5.2f1
5.6.0b10
2017.a1

Repro Steps:
1.) Download Repro project
2.) Build UWP Hololens app
3.) Open Sln and try to build app

Actual:
Error appears when trying to build the UWP app in visual studio

Error:
Severity Code Description Project File Line Suppression State
Error CS0006 Metadata file 'D:\Test\GeneratedProjects\UWP\Assembly-CSharp\bin\x86\Release\Assembly-CSharp.dll' could not be found

Severity Code Description Project File Line Suppression State
Error The command ""D:\Test\Unity\Tools\SerializationWeaver\SerializationWeaver.exe" "D:\Test\GeneratedProjects\UWP\Assembly-CSharp\bin\x86\Release\Unprocessed\Assembly-CSharp.dll" -pdb -verbose -unity-engine="D:\Test\uguitest\Unprocessed\UnityEngine.dll" -unity-networking="D:\Test\uguitest\Unprocessed\UnityEngine.Networking.dll" -additionalAssemblyPath="D:\Test\GeneratedProjects\UWP\Assembly-CSharp-firstpass\bin\x86\Release" "D:\Test\GeneratedProjects\UWP\Assembly-CSharp\obj\x86\Release\x86\Release"" exited with code 1.