Visual Studio 2017 bin\roslyn files locked during build

Question

I am running VS2017 version 26430.13 and every time I try to build a web project I get errors that access to the files in the bin\\roslyn is denied. Over a period of about 5 mi

Answer 1

Update the Microsoft.CodeDom.Providers.DotNetCompilerPlatform package to V1.0.6

Answer 2

Just open task manager and kill any instances of VBCSCompiler.exe. You don't even need to close Visual Studio.

Answer 3

In VS2017 & VS2019, this can happen when IIS Express is still running. Open the tray next to the clock, hover over the IIS Express icon running, right-click on the icon, click "Exit", confirm prompt, close active running worker processes. This can also be true when trying to publish your web project as well.