I've seen the upgrading videos. But in my case, everything is so screwed up I can't do a thing

Look at my inspector and atlas maker in the attachment, this happened immediately after I tried to use my UI atlas, that I had created previously. Is there a problem doing that? Atlases are now somehow different? I still have the atlas material and texture intact though... not sure what I can do with it now, maybe create a new atlas, with the material? how? but now I can't since I don't even have the atlas maker working...
Now I can't even undo this screwed up inspector and atlas maker, please help.
Thanks.
[EDIT]: seems like if I restart Unity, the inspector and atlas maker goes back live (AS LONG AS I DON'T SELECT THE OLD ATLAS AGAIN). But still, how can I use my old atlas? do I have to extract the sprites, and then add them again one by one? can't I just reuse my old stuff?
[EDIT]: I tried creating a new atlas, and specifying my old material, now when I tell a widget to use the atlas, it says there's no sprites found
