# Help with error message: Using 'app.import' with a file in the root of 'vendor/'

**URL:** <https://discuss.emberjs.com/t/help-with-error-message-using-app-import-with-a-file-in-the-root-of-vendor/6399>\
**Category:** Uncategorized\
**Created:** [October 2, 2014, 5:16am UTC](https://discuss.emberjs.com/t/help-with-error-message-using-app-import-with-a-file-in-the-root-of-vendor/6399 "2014-10-02T05:16:09Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Mithrilhall](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/mithrilhall/32/10074_2.png) [@Mithrilhall](https://discuss.emberjs.com/u/Mithrilhall)\
**Post date:** [October 2, 2014, 5:16am UTC](https://discuss.emberjs.com/t/help-with-error-message-using-app-import-with-a-file-in-the-root-of-vendor/6399/1 "2014-10-02T05:16:09Z")

</div>

When I start my ember application I get a bunch of these errors:

> Using `app.import` with a file in the root of `vendor/` causes a significant performance penalty. Pl ease move `vendor\bootstrap\dist\css\bootstrap-theme.css` into a subdirectory. Using `app.import` with a file in the root of `vendor/` causes a significant performance penalty. Pl ease move `vendor\bootstrap\dist\css\bootstrap.css` into a subdirectory. Using `app.import` with a file in the root of `vendor/` causes a significant performance penalty. Pl ease move `vendor\ember-addons.bs_for_ember\dist\css\bs-growl-notifications.min.css` into a subdirec tory.

This is the contents of my brocfile.js if it helps:

```
var EmberApp = require('ember-cli/lib/broccoli/ember-app');
var pickFiles = require('ember-cli/node_modules/broccoli-static-compiler');
var mergeTrees = require('ember-cli/node_modules/broccoli-merge-trees');

var app = new EmberApp();

var extraAssets = pickFiles('app', {
    srcDir: 'images',
    destDir: 'images'
});

app.import('bower_components/bootstrap/dist/js/bootstrap.js');
app.import('bower_components/bootstrap/dist/css/bootstrap.css.map', {
    destDir: 'assets'
});

var imageTree = mergeTrees([app.toTree(), extraAssets]);
module.exports = mergeTrees([app.toTree(), imageTree], { overwrite: true });

```

Any suggestions?

---

<div class="post-metadata">

**Author:** ![samwoodard](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.emberjs.com/samwoodard/32/14213_2.png) [@samwoodard](https://discuss.emberjs.com/u/samwoodard)\
**Post date:** [November 9, 2014, 6:18pm UTC](https://discuss.emberjs.com/t/help-with-error-message-using-app-import-with-a-file-in-the-root-of-vendor/6399/2 "2014-11-09T18:18:20Z")

</div>

When given an instance of EmberApp, when calling toTree, it now accepts extra trees to merge, like,

app.toTree([extraTree, [extraTree]]);

Hope this helps.