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

For Maven projects:

• Open the Maven Tool Window (for intellij users - right click on the project name and scroll down to the bottom to find the maven tool window) (indicated with this icon: )
• Click the Reimport All Maven Projects button (indicated with this icon: ).

Instructions: https://www.jetbrains.com/help/idea/maven-projects-tool-window.html