You might want to disable password protection to avoid the accidental locking of drawing files. If you forget a password, there is no way to recover the drawing as the password is required to open, inserted, or attach the drawing file. 
- Do one of the following: 
- Windows 7: Click the Windows Start button 
 Control Panel.  
- Windows 8: On the Windows Start screen, right-click (or use the swipe up gesture from the bottom edge of the screen) and click All Apps. Scroll to the Windows System section and click Control Panel. 
 
- Windows 8.1: On the Windows Start screen, click the All Apps button located near the lower-left corner of the screen (or use the swipe up gesture from the bottom edge of the screen). Scroll to the Windows System section and click Control Panel. 
 
  
- In the Control Panel window, click Programs, and then click Programs and Features. 
 
- From the installed application list, select the AutoCAD-based product, and then click Change or Uninstall/Change. 
 
- Click Add or Remove Features. 
 
- Specify whether Drawing Encryption is to be enabled or disabled. 
 
- Click Update and click Finish.