When an application layer creates or modifies files they are stored in the writeable sublayer. If the layer is then reset, the files in the writeable sublayer are deleted. This behavior lets you reset an application to the default state if settings become corrupted. However, many applications create data files that you do not want to lose when a layer is reset. These files need to be stored on the base file system and not in the layer to prevent potential loss.
For example, you create and activate a Microsoft Word layer. You do not create any layer exclude entries, global exclude entries, or data layers to redirect .doc files from the layer's writeable sublayer. You then activate the Microsoft Word layer and use it to create .doc files that you save on the computer's hard drive. If you then reset the Word layer, all of the .doc files you created are lost.
Table: Methods to prevent data loss