This is one of the new commands in AutoCAD 2008 that is sort of overlooked, but can save you a lot of time. If you use xrefs, then how many times have you had a problem with the parent drawing crashing? You might try running AUDIT or RECOVER on the parent drawing and find there are no errors, but you continue to have problems with this drawing.
Remember, if one of the child xrefs is corrupt, then this will affect your main drawing also. In the past, you would have to run RECOVER on each child drawing. If you had several xrefs, you might even have to open the main drawing and make note of the path and name of each drawing.
With RECOVERALL, you simply pick the main drawing and it, along with all the child xrefs are fed through the RECOVER command. All errors are fixed, and each drawing is saved in the current format.