diff --git a/lib/bootstrap-local.js b/lib/bootstrap-local.js
index a4e2d58e3438..a4043c34437f 100644
--- a/lib/bootstrap-local.js
+++ b/lib/bootstrap-local.js
@@ -12,7 +12,7 @@ global.angularCliPackages = require('./packages');
 const compilerOptions = JSON.parse(fs.readFileSync(path.join(__dirname, '../tsconfig.json')));
 
 const oldRequireTs = require.extensions['.ts'];
-require.extensions['.ts'] = function(m, filename) {
+require.extensions['.ts'] = function (m, filename) {
   // If we're in node module, either call the old hook or simply compile the
   // file without transpilation. We do not touch node_modules/**.
   // We do touch `Angular CLI` files anywhere though.
@@ -52,6 +52,9 @@ if (!__dirname.match(new RegExp(`\\${path.sep}node_modules\\${path.sep}`))) {
   const Module = require('module');
   const oldLoad = Module._load;
   Module._load = function (request, parent) {
+    if (request.match(/ts-node/) && parent && parent.id && parent.id.match(/karma/)) {
+      throw new Error();
+    }
     if (request in packages) {
       return oldLoad.call(this, packages[request].main, parent);
     } else if (request.startsWith('@angular/cli/')) {