Builds failing to start with access denied to Microsoft.AspNetCore.Razor.Language.dll

[pakrym]

https://dev.azure.com/dnceng/public/_build/results?buildId=101370&view=logs

##[section]Starting: Initialize job
Current agent version: '2.147.1'
Prepare build directory.
##[error]One or more errors occurred. (One or more errors occurred. (Access to the path 'E:\A\_work\3\s\.nuget\packages\microsoft.net.sdk.razor\3.0.0-preview-19107-04\tools\netcoreapp3.0\Microsoft.AspNetCore.Razor.Language.dll' is denied.)) (Access to the path 'E:\A\_work\3\s\.nuget\packages\microsoft.net.sdk.razor\3.0.0-preview-19107-04\tools\netcoreapp3.0\Microsoft.AspNetCore.Razor.Language.dll' is denied.)
##[section]Finishing: Initialize job

cc @pranavkm @natemcmaster

[natemcmaster]

cc @dougbu - looks like the kill processes step didn't cleanup whatever is using this file.

@pranavkm @ajaybhargavb - we still have Razor/Mvc tests in this repo that invoke dotnet build, right? Do they always use -nodeReuse:false? If not they, might be the source of the issue.

[pranavkm]

we still have Razor/Mvc tests in this repo that invoke dotnet build, right?

AFAIK, not in the master branch. That's part of AspNetCore-Tooling and we do /nr:false there in our builds. We would use rzc to compile Razor files in the solution, so if the actual repo was built with /nr:true you'd see this issue.

[pranavkm]

In this build - https://dev.azure.com/dnceng/public/_build/results?buildId=101617, I see a couple of other files running in to the same sort of issue:

One or more errors occurred. (One or more errors occurred. (Access to the path 'E:\A\_work\2\s\.dotnet\x64\dotnet.exe' is denied.)) (One or more errors occurred. (Access to the path 'E:\A\_work\2\s\.dotnet\x64\shared\Microsoft.NETCore.App\3.0.0-preview-27324-5\clrcompression.dll' is denied.)) (Access to the path 'E:\A\_work\2\s\.dotnet\x64\dotnet.exe' is denied.) (Access to the path 'E:\A\_work\2\s\.dotnet\x64\shared\Microsoft.NETCore.App\3.0.0-preview-27324-5\clrcompression.dll' is denied.)

One or more errors occurred. (One or more errors occurred. (Access to the path 'E:\A\_work\2\s\.dotnet\x64\dotnet.exe' is denied.)) (One or more errors occurred. (Access to the path 'E:\A\_work\2\s\.dotnet\x64\shared\Microsoft.NETCore.App\3.0.0-preview-27324-5\Microsoft.Win32.Primitives.dll' is denied.)) (Access to the path 'E:\A\_work\2\s\.dotnet\x64\dotnet.exe' is denied.) (Access to the path 'E:\A\_work\2\s\.dotnet\x64\shared\Microsoft.NETCore.App\3.0.0-preview-27324-5\Microsoft.Win32.Primitives.dll' is denied.)

[natemcmaster]

I believe this has been addressed by #7793