Ember CLI throws Unhandled 'error' event message - ember.js

Question

Ember CLI works great most of the time on my laptop. However, once in a while (very very occasionally) when I ctrl + c the ember server process and restart it, it throws the following error and refuses to start again until I do a complete system restart (I am on a Mac):
MacBook-Pro:client-web User$ ember server
version: 1.13.6
Could not find watchman, falling back to NodeWatcher for file system events.
Visit http://www.ember-cli.com/user-guide/#watchman for more info.
2015-09-04 17:46 ember[1102] (FSEvents.framework) FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-21)
2015-09-04 17:46 ember[1102] (FSEvents.framework) FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-21)
Livereload server on http://localhost:49152
Serving on http://localhost:4200/
2015-09-04 17:46 ember[1102] (FSEvents.framework) FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-21)
events.js:85
throw er; // Unhandled 'error' event
^
Error: watch EMFILE
at exports._errnoException (util.js:746:11)
at FSEvent.FSWatcher._handle.onchange (fs.js:1157:26)
Why does this happen? I want to avoid doing system restarts.

Answer 1

Adding this as an answer because the Ember CLI docs no longer mention it, and it took me a while to track down:
Frequently, this problem is caused by Sublime Text watching the same files as the Ember server. If you're using Sublime and encountering this error, try closing Sublime and running the server again. To keep it from recurring, you can tell Sublime Text to ignore the tmp directory, by adding "tmp/*" to the"folder_exclude_patterns" in your Sublime user settings.