Merge pull request #7269 from wiwei/restartit

Add another troubleshooting step for msb4u integration

Author: wiwei

Documentation/Tools/HolographicRemoting.md

@@ -25,7 +25,7 @@ configure the project using the following steps.
 
 ### Debugging HoloLens 2 remoting via Unity package import
 
-If HoloLens 2 hand joints and eye tracking aren't working over remoting, there are three common points of potential issues. They're listed below in the order they should be checked.
+If HoloLens 2 hand joints and eye tracking aren't working over remoting, there are a few common points of potential issues. They're listed below in the order they should be checked.
 
 #### MSBuildForUnity package import via writing into the package.manifest
 
@@ -45,7 +45,21 @@ For the third point, navigate to the Unity Player Settings. From there, under th
 
 ![DotNetWinRT Present](../Images/Tools/Remoting/DotNetWinRTPresent.png)
 
-After all three of those, hand joints over remoting should be working! If not, there might be something misconfigured in the profiles for general hand joints on-device. In that case, please [reach out on one of our help resources](../GettingStartedWithTheMRTK.md#getting-help).
+#### Failure to find dotnet.exe
+
+MSBuild for Unity depends on dotnet.exe existing in the system path - dotnet.exe must both be
+installed and present in the PATH environment variable. If neither of those requirements are
+ true, this error may manifest in the Unity console:
+
+```
+Win32Exception: ApplicationName='dotnet', CommandLine='msbuild DotNetAdapter.csproj -restore  -v:minimal -p:NuGetInteractive=true  -t:Build -p:Configuration=Release -nologo', CurrentDirectory='C:\src\Assets\MixedRealityToolkit.Providers\WindowsMixedReality\Shared\DotNetAdapter', Native error= The system cannot find the file specified.
+```
+
+The solution to this is to ensure that the [.NET Core CLI tools are installed]
+(https://docs.microsoft.com/en-us/dotnet/core/tools/?tabs=netcore2x) and reboot the system
+to force all apps to get a refreshed system path.
+
+If hand joints over remoting are still not working after following the above steps, there might be something misconfigured in the profiles for general hand joints on-device. In that case, please [reach out on one of our help resources](../GettingStartedWithTheMRTK.md#getting-help).
 
 ### Removing HoloLens 2-specific remoting support