playframework/Play20 — comment on commit 49163e48957f5670545da15bd859c9e7ad2a7243
File:  line 0
By hseeberger:

Now I see the issue: When you run _clean_ __after__ _eclipsify_, you delete the folder _target/scala-2.9.1/_, which was added as a source folder to _.classpath_, when you ran _eclipsify_.

Please try the following order:
1. _play clean_
2. _play eclipsify_ (which will run _compile_ anyway)