You actually get quite a lot of info by that error.
First it says it can’t read the property name of undefined, meaning you are accessing someobject.name somewhere. A first thing you could try is searching your whole project for “.name” (without quotes). Might turn up a lot of results, or might turn up only a few. To actually find the .name that’s causing the issue. Just do a console.log on the object itself right before you access it’s name property. If it returns null or undefined at some point you know that’s the culprit (or one of them)
Secondly, those exceptions mostly pop up when you’re working in rendered or destroyed callbacks from templates. In other words, chances are high that you can narrow your search down to “.name” inside rendered or destroyed callbacks.
As to fixing the bug, that depends on the actual code and context. Might be as simple as checking the type of the object before accessing it’s name property and if it’s null aborting the code that follows, but might also be somewhat more complex.
You should be able to track it down with this info, if you have problems resolving the bug, feel free to post the code that’s causing the errors.