title: Azure Devops - dotnetcore build fails consistently - process failed to start
body: <p>Am setting up a small project build, which is in .Net Core. <code>dotnet build</code> fails everytime with below log:</p>
  
  <pre><code>2019-10-03T21:31:54.5434435Z ##[section]Starting: dotnet build
  2019-10-03T21:31:54.5559431Z ==============================================================================
  2019-10-03T21:31:54.5559511Z Task         : .NET Core
  2019-10-03T21:31:54.5559544Z Description  : Build, test, package, or publish a dotnet application, or run a custom dotnet command
  2019-10-03T21:31:54.5559595Z Version      : 2.158.0
  2019-10-03T21:31:54.5559626Z Author       : Microsoft Corporation
  2019-10-03T21:31:54.5559679Z Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/build/dotnet-core-cli
  2019-10-03T21:31:54.5559712Z ==============================================================================
  2019-10-03T21:31:55.3428758Z [command]C:\windows\system32\chcp.com 65001
  2019-10-03T21:31:55.3566253Z Active code page: 65001
  2019-10-03T21:31:55.5334629Z [command]C:\hostedtoolcache\windows\dotnet\dotnet.exe build d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool.csproj --no-restore
  2019-10-03T21:31:55.5534100Z ##[error]Error: There was an error when attempting to execute the process 'C:\hostedtoolcache\windows\dotnet\dotnet.exe'. This may indicate the process failed to start. Error: spawn C:\hostedtoolcache\windows\dotnet\dotnet.exe ENOENT
  2019-10-03T21:31:55.5546833Z ##[error]Dotnet command failed with non-zero exit code on the following projects : d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool.csproj
  2019-10-03T21:31:55.5625878Z ##[section]Finishing: dotnet build
  
  </code></pre>
  
  <p>I have now added a dotnet SDK activity to load <code>2.2.x</code> version and then then an explicit <code>dotnet restore</code> step (even though its not needed technically as <code>build</code> should do a <code>restore</code> too). But, the <code>restore</code> step passes, but it fails every time in the <code>build</code> step.</p>
  
  <p><a href="https://i.stack.imgur.com/wcjnU.png" rel="noreferrer"><img src="https://i.stack.imgur.com/wcjnU.png" alt="enter image description here"></a></p>
  
  <p>Some partial logs from the <code>restore</code> process are shown below -</p>
  
  <pre><code>2019-10-03T21:30:25.5826687Z ##[section]Starting: dotnet restore
  2019-10-03T21:30:25.5942577Z ==============================================================================
  2019-10-03T21:30:25.5942669Z Task         : .NET Core
  2019-10-03T21:30:25.5942702Z Description  : Build, test, package, or publish a dotnet application, or run a custom dotnet command
  2019-10-03T21:30:25.5942756Z Version      : 2.158.0
  2019-10-03T21:30:25.5942787Z Author       : Microsoft Corporation
  2019-10-03T21:30:25.5942837Z Help         : https://docs.microsoft.com/azure/devops/pipelines/tasks/build/dotnet-core-cli
  2019-10-03T21:30:25.5942869Z ==============================================================================
  2019-10-03T21:30:27.1500592Z [command]C:\windows\system32\chcp.com 65001
  2019-10-03T21:30:27.7292436Z Active code page: 65001
  2019-10-03T21:30:27.7296084Z SYSTEMVSSCONNECTION exists true
  2019-10-03T21:30:28.0692275Z SYSTEMVSSCONNECTION exists true
  2019-10-03T21:30:28.5211540Z SYSTEMVSSCONNECTION exists true
  2019-10-03T21:30:28.5240738Z Saving NuGet.config to a temporary config file.
  2019-10-03T21:30:28.5284543Z Saving NuGet.config to a temporary config file.
  2019-10-03T21:30:28.5338058Z [command]C:\hostedtoolcache\windows\dotnet\dotnet.exe restore d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool.csproj --configfile d:\a\_temp\Nuget\tempNuGet_05ce1f4cc83beb812b37be120d7010969ab1a363.config --verbosity Detailed
  2019-10-03T21:30:31.1552382Z 
  2019-10-03T21:30:31.1633338Z Welcome to .NET Core!
  2019-10-03T21:30:31.1633445Z ---------------------
  2019-10-03T21:30:31.1633487Z Learn more about .NET Core: https://aka.ms/dotnet-docs
  2019-10-03T21:30:31.1633556Z Use 'dotnet --help' to see available commands or visit: https://aka.ms/dotnet-cli-docs
  2019-10-03T21:30:31.1633582Z 
  2019-10-03T21:30:31.1633618Z Telemetry
  2019-10-03T21:30:31.1633654Z ---------
  2019-10-03T21:30:31.1633712Z The .NET Core tools collect usage data in order to help us improve your experience. The data is anonymous and doesn't include command-line arguments. The data is collected by Microsoft and shared with the community. You can opt-out of telemetry by setting the DOTNET_CLI_TELEMETRY_OPTOUT environment variable to '1' or 'true' using your favorite shell.
  2019-10-03T21:30:31.1633881Z 
  2019-10-03T21:30:31.1633924Z Read more about .NET Core CLI Tools telemetry: https://aka.ms/dotnet-cli-telemetry
  2019-10-03T21:30:31.1684350Z 
  2019-10-03T21:30:31.1686360Z Configuring...
  2019-10-03T21:30:31.1686911Z --------------
  2019-10-03T21:30:31.1687446Z A command is running to populate your local package cache to improve restore speed and enable offline access. This command takes up to one minute to complete and only runs once.
  2019-10-03T21:30:44.4629886Z Decompressing .......... 13256 ms
  2019-10-03T21:31:36.6357349Z Expanding .......... 51984 ms
  2019-10-03T21:31:38.0761886Z 
  2019-10-03T21:31:38.0762691Z ASP.NET Core
  2019-10-03T21:31:38.0762874Z ------------
  2019-10-03T21:31:38.0763054Z Successfully installed the ASP.NET Core HTTPS Development Certificate.
  2019-10-03T21:31:38.0763284Z To trust the certificate run 'dotnet dev-certs https --trust' (Windows and macOS only). For establishing trust on other platforms refer to the platform specific documentation.
  2019-10-03T21:31:38.0763446Z For more information on configuring HTTPS see https://go.microsoft.com/fwlink/?linkid=848054.
  2019-10-03T21:31:38.4176357Z Build started 10/3/2019 9:31:38 PM.
  2019-10-03T21:31:38.9605866Z      0&gt;Resolving SDK 'Microsoft.NET.Sdk'...
  2019-10-03T21:31:38.9816247Z        Property reassignment: $(MSBuildProjectExtensionsPath)="d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\obj\" (previous value: "obj\") at C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Current\Microsoft.Common.props (56,5)
  2019-10-03T21:31:38.9833374Z        Property reassignment: $(MSBuildAllProjects)=";C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\Sdk\Sdk.props;C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.props" (previous value: ";C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\Sdk\Sdk.props") at C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.props (15,5)
  2019-10-03T21:31:38.9949011Z        Property reassignment: $(MSBuildAllProjects)=";C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\Sdk\Sdk.props;C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.props;C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.DefaultItems.props" (previous value: ";C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\Sdk\Sdk.props;C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.props") at C:\hostedtoolcache\windows\dotnet\sdk\2.2.402\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.DefaultItems.props (21,5)
  ...
  ...
  ...
  2019-10-03T21:31:47.9997847Z          Generating MSBuild file d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\GDPR.OutputProvider\obj\GDPR.OutputProvider.csproj.nuget.g.props.
  2019-10-03T21:31:47.9998017Z          Generating MSBuild file d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\GDPR.OutputProvider\obj\GDPR.OutputProvider.csproj.nuget.g.targets.
  2019-10-03T21:31:48.0229473Z          Writing assets file to disk. Path: d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\GDPR.OutputProvider\obj\project.assets.json
  2019-10-03T21:31:48.0229714Z          Checking compatibility of packages on .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0229774Z          Checking compatibility for GDPR.Output.IO 1.0.0 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0229817Z          Checking compatibility for NETStandard.Library 2.0.3 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0229859Z          Checking compatibility for GDPR.Common 1.0.0 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0229916Z          Checking compatibility for GDPR.Logger 1.0.0 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0229955Z          Checking compatibility for GDPR.ObjectModel 1.0.0 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0229996Z          Checking compatibility for WindowsAzure.Storage 9.3.3 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0230054Z          Checking compatibility for Microsoft.NETCore.Platforms 1.1.0 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0230299Z          Checking compatibility for Microsoft.Azure.KeyVault 3.0.3 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0230341Z          Checking compatibility for Microsoft.Azure.Management.KeyVault 2.4.3 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0230394Z          Checking compatibility for Microsoft.Azure.Services.AppAuthentication 1.0.3 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0230457Z          Checking compatibility for Microsoft.IdentityModel.Clients.ActiveDirectory 5.0.5 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0230500Z          Checking compatibility for Microsoft.Rest.ClientRuntime.Azure.Authentication 2.4.0 with .NETStandard,Version=v2.0.
  2019-10-03T21:31:48.0230543Z          Checking compatibility for System.Security.Cryptography.X509Certificates 4.3.2 with .NETStandard,Version=v2.0.
  ...
  ...
  ...
  2019-10-03T21:31:54.4289388Z          All packages and projects are compatible with .NETCoreApp,Version=v2.1.
  2019-10-03T21:31:54.4454996Z          Committing restore...
  2019-10-03T21:31:54.4459080Z          Generating MSBuild file d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\obj\MyTool.csproj.nuget.g.props.
  2019-10-03T21:31:54.4460039Z          Generating MSBuild file d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\obj\MyTool.csproj.nuget.g.targets.
  2019-10-03T21:31:54.4461496Z          Writing assets file to disk. Path: d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\obj\project.assets.json
  2019-10-03T21:31:54.4567260Z          Writing cache file to disk. Path: d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\obj\MyTool.csproj.nuget.cache
  2019-10-03T21:31:54.4573630Z          Restore completed in 4.12 sec for d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool.csproj.
  2019-10-03T21:31:54.4661557Z          
  2019-10-03T21:31:54.4662703Z          NuGet Config files used:
  2019-10-03T21:31:54.4663349Z              d:\a\_temp\Nuget\tempNuGet_05ce1f4cc83beb812b37be120d7010969ab1a363.config
  2019-10-03T21:31:54.4664039Z          
  2019-10-03T21:31:54.4664744Z          Feeds used:
  2019-10-03T21:31:54.4665067Z              https://api.nuget.org/v3/index.json
  2019-10-03T21:31:54.4785886Z          
  2019-10-03T21:31:54.4786633Z          Installed:
  2019-10-03T21:31:54.4796944Z              7 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\MyTool.Logger\MyTool.Logger.csproj
  2019-10-03T21:31:54.4803020Z              32 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\MyTool.Common\MyTool.Common.csproj
  2019-10-03T21:31:54.4803472Z              33 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\MyTool.OutputProvider\MyTool.OutputProvider.csproj
  2019-10-03T21:31:54.4803792Z              34 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\MyTool.Output.IO\MyTool.Output.IO.csproj
  2019-10-03T21:31:54.4804056Z              33 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\MyTool.SearchFilter\MyTool.SearchFilter.csproj
  2019-10-03T21:31:54.4804362Z              32 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\MyTool.PiiData\MyTool.PiiData.csproj
  2019-10-03T21:31:54.4805159Z              42 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool\MyTool.SearchHandler\MyTool.SearchHandler.csproj
  2019-10-03T21:31:54.4805573Z              42 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool.App\MyTool.App.csproj
  2019-10-03T21:31:54.4805849Z              46 package(s) to d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool.csproj
  2019-10-03T21:31:54.4806121Z        Done executing task "RestoreTask".
  2019-10-03T21:31:54.4806389Z      1&gt;Done building target "Restore" in project "MyTool.csproj".
  2019-10-03T21:31:54.4806658Z      1&gt;Done Building Project "d:\a\r1\a\MyTool\DataFactory\CustomActivities\MyTool\MyTool.csproj" (Restore target(s)).
  2019-10-03T21:31:54.5031887Z 
  2019-10-03T21:31:54.5032209Z Build succeeded.
  2019-10-03T21:31:54.5032251Z     0 Warning(s)
  2019-10-03T21:31:54.5032319Z     0 Error(s)
  2019-10-03T21:31:54.5032343Z 
  2019-10-03T21:31:54.5032377Z Time Elapsed 00:00:16.08
  2019-10-03T21:31:54.5417968Z ##[section]Finishing: dotnet restore
  </code></pre>
  
  <p>Any clues what could be going wrong?</p>