Hey
My notes from my math course is corrupt and i really need them. When i open the document it just say "worksheet may be incomplete" Can anyone help recovering them? I tried the recover function but it didn't work. Here is the original document: Mat_1_-_Noter.mw. 

I also have this .bak from the day before where i know it worked:   _Users_jonathanlarsen_Desktop_Mat_1_-_Noter70_MAS.bak.zip
How can i prevent this in the future? It's the second time it has happenend.

Sincerely a frustrated student :(