Unresolved reference on everything

I created a kotlin project and it was working fine.

But now it’s throwing an error on everyhing(Int, Array, println…)

I tried removing the kotlin module and recofnigure it and it didn’t work.

Strange thing is that when I do “Invalidate Caches/Restart” from the File menu,

the content of the project disappears.

I created my project as
New Project → Java → Kotlin/JVM

And now I created a file and the error is thrown right away.

Have you tried closing the project, deleting .idea directory and test.iml file and then using File->New->Project from Existing Sources... (or Import project... on project selection screen if you do not have any project opened)?

Sorry for the late reply.
After doing that, my project lost all kotlin and java related functions.
The module no longer has java and kotlin dependencies.

I tried to make a new module and it created new src folder.
Are there any way to change the existing module settings?

Select the module in ‘Project’ tab and press F4.

Unlike other normal modules this module doesn’t have the proper tabs.

If I add another module to this project, the created module seems normal.

This one seems immutable.

I would like to show the screenshot of it, but I already uninstalled IDEA.

I already have reinstalled it several times but the same error keep occurs, so I decided to move on to eclipse.