Disappearing layers

[langerhans]

Working on a drawing with about 30 layers in Architecture 2014.

I turned all of them off for a minute, intending to turn just one back on to work on it. Now they won't come back. I selected all and turned the "lightbulb" on. I was able to get one layer to show up but the rest won't turn on. Nothing is locked or frozen. I have closed and reopened the drawing, changed the view style, restarted the computer, even opened it in Autocad on a Mac. Nothing worked. 

How can I get these layers to be visible again?

[Swagnificent]

Have you tried "LAYERP", then REGENALL?

[dbroad]

Might you have isolated/hidden vs turned layers off?  If so, there would be a red lightbulb on the status line.

[langerhans]

Thanks all for the suggestions. Same as before. I also tried to copy all and paste in a new drawing; didn't work. Any ideas on how I can save this drawing?

[dbroad]

If recover won't fix it, go to the backup.  Whatever you do, don't save it in a corrupted state or you will lose your backup.  Copy/paste will only work if there is something to copy.  If your backup is already gone, start from scratch.