I haven’t got any errormessages or anything, the map has just ceased to exist.
I stoped working 20:00 with my map, but all the saves and autosaves are from 11:00. So there is a 9 hour gap that hasn’t been saved, even tho I have saved manually/automatically.
Possibly you’ve created a second project in documents and settings or some other location it isn’t finding. Try finding the project in Windows explorer, searching for .uproject OR you could open the editor without launching your thumbnailed project and choose Recent Projects within the editor.
Alternatively, your map is in the thumbnailed project but you renamed it and it’s instead opening an earlier map set as the default editor start up map.
[or maybe it did cease to exist]
I guess you know, but for a given project, maps are usually in “/Content/Maps/”