Question: After importing an existing project into RubyMine, I encountered "Rails server launcher wasn't found in the project" when I Run/Edit Configuration. 

I've checked this [Cannot start the debugger in Rubymine. Rails server launcher wasn't found in project](https://stackoverflow.com/questions/27883244/cannot-start-the-debugger-in-rubymine-rails-server-launcher-wasnt-found-in-pro), but deleting the .idea directory and re-open is not helpful. 

I can `rails server` in the Terminal successfully and the rails server runs. So I guess it's likely a RubyMine related thing.

Thanks,
Allen

Answer: 
The easiest way to fix it:

1. Close project
2. Remove `.idea` folder from project folder
3. Open project

Bingo!

NOTE: this workaround seems to no longer work with 2017.2. See [RUBY-20144](https://youtrack.jetbrains.com/issue/RUBY-20144)
I've came across this same problem, and a way I found to solve it was to properly defining the root folder of the project when opening it in the first time with RubyMine.

As far as I can understand, ideally you should open the project by pointing the RubyMine to the project's root folder:

```
my-workplace/
|-- rails-project-name/  <-- point RubyMine here when openning
|   |-- app/
|   |-- bin/
|   |-- config/
|   |-- db/
|   |-- lib/
|   |-- log/
|   |-- public/
|   |-- test/
|   ...

```