IntelliJ IDE | .iml File lost or deleted

Question

Last week I was working on a Java EE project with IntelliJ IDE.

Today: As I started up my IntelliJ 2016.1 it gave me the error:

Error Loading Project

Answer 1

The Gradle refresh did not work in my case. Several project folders were also missing, so I could not copy/paste new .iml files either.

However when I opened the project anew, choosing Delete Existing Project and Import, the project was able to recreate all the .iml files.