This topic provides expanded information about errors and warnings in Revit Architecture (from Revit 2010 Help - this section doesn't appear in 2011 Help).
Curtain Walls
Copy and Paste
Message
Cannot paste selection in [name] view.
Elements were deleted. Use Edit Pasted Elements to keep them.
Details
Problem: Revit Architecture is unable to paste the selected component in the view.
Solution: If you tried to paste a wall in an elevation view or a section view, you see this message. Try pasting in a plan, reflected ceiling plan, or 3D view. This message also displays if you try to paste a group of components that cannot be pasted into a certain view, for example, a column group into an elevation view.
Problem: Revit Architecture requires a proper host for the copied element. For example, a window needs a wall, and a tag or dimension needs reference elements.
Solution: If you tried to paste an element into a location that does not contain a proper host, you see this message. Click Cancel to remove the warning. On the ribbon, click Edit Pasted Elements. In Edit Pasted mode, place the copied element on its proper host. Click Finish to complete the paste process.
TipThe Paste Aligned tool does not provide the Edit Pasted Elements button. If you see this message, you can cancel, and use the Paste tool instead.
Also see Editing Pasted Elements.
Roofs
Sketching
Worksets
Message
The central file has been restored from a previous backup. As a result, the following workset(s) edited by you have been rolled back.
Details
Problem: You had a workset editable by you in this local file. Another user has replaced the central file with a previous backup copy, where the workset you are editing either does not exist or has a previous version.
Solution: Find out why the central file was restored. If it must stay restored, you have to redo your changes again, by making another local copy. You can copy elements from your current local copy, if that is helpful.