diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ca3ba94d..934c5059 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -122,7 +122,7 @@ jobs:
       - name: Install Python on Windows
         if: matrix.os == 'windows-2019'
         run: |
-          if ( $PLATFORM -eq "x86_64" )
+          if ( ${Env:PLATFORM} -eq "x86_64" )
           {
             Set-Variable -name py_arch -value "-amd64"
           }
@@ -131,9 +131,9 @@ jobs:
             Set-Variable -name py_arch -value ""
           }
           Write-Output "py_arch: $py_arch"
-          Set-Variable -name python_file -value "python-${BUILD_PYTHON_VERSION}${py_arch}.exe"
+          Set-Variable -name python_file -value "python-${Env:BUILD_PYTHON_VERSION}${py_arch}.exe"
           Write-Output "python_file: $python_file"
-          Set-Variable -name python_url -value "https://www.python.org/ftp/python/$BUILD_PYTHON_VERSION/$python_file"
+          Set-Variable -name python_url -value "https://www.python.org/ftp/python/${Env:BUILD_PYTHON_VERSION}/${python_file}"
           Write-Output "python_url: $python_url"
           Invoke-WebRequest -Uri $python_url -OutFile $python_file
           Start-Process -wait -FilePath $python_file -ArgumentList "/quiet","InstallAllUsers=1","TargetDir=c:\\python"