Low-level debugging is available at any time even if the program was not compiled with any debugging options, but you must use absolute addresses to access variables, so you'll need a listing of your program. Low-level debugging is convenient when you're debugging a data-dependent problem on a client's machine, if the client does not have a debug-version of your program. TheTrace Files command described in File Tracing operates in this mode. Trace Files is particularly useful for tracking data-specific problems in complex applications.