revit problem - can't modify

[dooher-o590466]

wonder can anybody help me. I have been designing a museum for a university project. Tryed to save it yesterday. Today I can do nothing with it i can delete or add anything new. I tryed to copy it to a new project sheet and it still wont work. Can somebody help me as it is due in a few days

[damon.sidel]

A little more information might be helpful.
What are deleting or adding? In what view are you working? What version of Revit are you using?

[jcoe]

Check to see if you opened the file in Revit Architecture Viewer by mistake. When you are inside viewer mode there is no distinct difference except you cannot save, print or export.