By saving your work frequently, you can ensure a minimum of lost data if your system fails. Computer hardware problems, power surges, user mistakes, or software problems can cause errors that prevent you from editing or plotting the drawing.
When an error occurs, AutoCAD LT tries to record diagnostic information in the aclt.err file, which you can use to report a problem. AutoCAD LT marks a drawing as damaged if it detects corrupted data or if you request that the drawing be saved after a system failure. If the damage is minor, you sometimes can repair the drawing simply by opening it.
You can use RECOVER to perform an audit on and attempt to open any file you select. Use AUDIT to find and correct errors in open file.
Example: Auditing Files
The output from a recovery audit is written to an ADT log file if the AUDITCTL system variable is set to 1 (on).
Recovery does not necessarily preserve the high-level consistency of the drawing file. AutoCAD LT tries to extract as much material as it can from the damaged file.