Levels missing Add Existing button gone too

My computer crashed last night, as my Windows system does. It’s not an old system it’s brand new. But still it crashes like hell when I run Unreal.

The problem is THIS time it removed at least one level from my game that I can see, a lynchpin level that connects all the others. On disk my level still seems to be there. However in my game it’s gone. If I try to Open the level it does not show up in my list in my map folder (and again on disk it is there).

In the Levels drop down I CANNOT see the “Add Existing” option now in my game.

I can do this if I load up a different game, but this will not work in my game any longer… you know the one I’ve put one million hours into.

How do I fix something when the button I need is gone???

So far to fix this I have gone to Unreal 4.12.5. This did nothing to alleviate the problems.

I then installed Unreal 4.13.0. This didn’t work

I reloaded my lynchpin from backup. This did nothing to fix my problems.

How do I fix something when the “Add Existing” button that I need to fix it, is gone???

I’m stumped, and somewhat panicked that my game has just gotten badly screwed.

Whenever my system crashes on me, ther is a 50/50 chance of getting some assets corrupted.
Sometimes its meshes, sometimes materuals, sometimes levels.

The only thing that helps here is a backup.
Personally, I make incremental backups every 30 minutes.