Some backup packages will come back later and retry, but most open applications will still be open and, therefore files will get skipped again. Users get locked out of their applications. The backup could get forced. If any changes occur to a file during the backup of that file, parts of the changes might get captured by the backup software while other parts may be in areas of the file that have already been read for the backup. The data will be corrupt.
Users are able to continue using their software, hardware and operating system.
Windows NT 4.0 Workstation and Windows 2000 Professional. Benefits to Administrator Files won't get skipped. Users won't get locked out of their applications or chased off the network. The copy of data is solid, even if the file was changing during the backup. No need to worry about grouping files.