Severity Code Description Project File Line Suppression State Error MSB3027 Could not copy "obj\Debug\netcoreapp2.1\KodingAttitudeApp.dll" to "bin\Debug\netcoreapp2.1\KodingAttitudeApp.dll". Exceeded retry count of 10. Failed. The file is locked by: ".NET Core Host (9280)" KodingAttittudeApp C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets 4194

 Severity Code Description Project File Line Suppression State Error MSB3027   Could not copy "obj\Debug\netcoreapp2.1\KodingAttitudeApp.dll" to "bin\Debug\netcoreapp2.1\KodingAttitudeApp.dll". Exceeded retry count of 10. Failed. The file is locked by: ".NET Core Host (9280)" KodingAttittudeApp C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\Microsoft.Common.CurrentVersion.targets 4194

To resolve this issue 

1. Close the Visual Studio Application and 

2. Delete the obj and bin folders

if unable delete the bin folder and gets the error dialog box with Try again or Skip

"The action can't be completed because the file is open in dotnet.exe"

3. then go to Task Manager from the Task bar and select .NET Core Host and click on End task button. The the issue will be resolved