logic 9 illegal fomat of file

So I'm cranking through my project - saving as I edit. 4 go great - no problem. 5th save - Freaks out LP9. I see the save in my documents, but can't import or open because the prompt says : READ ERROR !!! Illegal format of file.

I saw a tip to open as an .lso. That only creates a jpeg and not help with my challenge.

Any words of wisdom?

Thanks