How do I remove a fatal error in Autodesk Revit 2018?

Answer 1

You can remove stored warnings by purging the unused items in the project, but a fatal warning is something telling you the program has suffered a fatal error, from which it cannot recover. If it gives you the option to save it as a backup copy, save it. If not, you will learn to set your save reminders so as to minimize your time rebuilding what you lost. The best solution would be to determine why the fatal error occurred.