If the Read-only property is set for a file by the OS tools, then:
–This file is opened in the view mode.
–A notification “The document is view-only” is displayed on the Toolbar.
In the view mode, you cannot make changes to the document or change its formatting. If necessary, you can create a copy of this document that can be edited. To do this, on the Toolbar, click Edit a copy.
A copy of the document will open in a new application window. To save the file copy, follow the steps described in the Save a file section.