diff --git a/eng/build.ps1 b/eng/build.ps1
index cfde8fbd567a335fc0a8baf85cf2ea395fb7f47f..fde416bd241fe43630510d6557ffed950d27a1eb 100644
--- a/eng/build.ps1
+++ b/eng/build.ps1
@@ -655,6 +655,10 @@ try {
   }
 
   if ($launch) {
+    if (-not $build) {
+      InitializeBuildTool
+    }
+
     $devenvExe = Join-Path $env:VSINSTALLDIR 'Common7\IDE\devenv.exe'
     &$devenvExe /rootSuffix RoslynDev
   }