This tool will recover a drawing and all of it's Xrefs then provide you with a report! It maintains the original file's format, Saves the original as a *.BAK, and updates custom objects if an object enabler is present.
The sad thing is that it is not there in AutoCAD MEP. The cool thing is the command line version is there. Type "Recoverall" to invoke the tool and fix those messed up background you keep getting from your clients.