You open drawings to work on them just as you do with other applications.
DWG, DWT, and DWS files created with Autodesk applications and RealDWG™-based applications are trusted by Autodesk. When you open a TrustedDWG file, the following icon displays in the status bar.
For more information about TrustedDWG, click the TrustedDWG icon.
Each time you start the product, the last folder that you used for opening or saving a file is set as the default path in the standard file selection dialog box. Alternatively, you can specify a fixed default folder with the program shortcut icon in Windows. For specific instructions, see the topic To Change the Default Drawing Folder.
When you open a drawing, you are notified when an external reference such as an xref, image, or underlay cannot be located. If the external reference was moved to a different folder or drive, use the External References palette to locate the file.
In some circumstances, it is possible that a drawing file becomes corrupted. This can result from hardware problems or transmission errors. If a drawing file is corrupt, you might be able to recover it:
If you cannot recover a drawing file, rename the drawing's .bak file to a similar name specifying a .dwg extension. If the .bak file is also corrupt, hopefully you can access a copy from a backup device or location.