MSBuild Error MSB4025 when using Sealights Agent

Problem

In certain cases integrating our agent as part of MSBuild causes the build to fail with 'Error MSB4025: The project file could not be loaded. Could not find file ... .metaproj'

Solution

This can be solve by doing the following - depending on your MSBuild version.

MSBuild version 14

Set the MSBuildEmitSolution environment variable to 1 before running MSBuild itself.

set MSBuildEmitSolution=1
Msbuild SlnFolders.sln

MSBuild version 15

Add the --msBuildVersion 15 flag to the Sealights' .NET agent prepareForMsBuild command:

SL.DotNet.exe prepareForMsBuild  --buildSessionIdFile buildSessionId.txt --workspacePath "C:\path\to\project" --msBuildVersion 15