You need to be on OBM v5.0 or above, as well as support from the underlying OS. Windows XP and
2003, by default, come with Volume Shadow Copy, which allows backup open file. For older platforms, e.g. Windows 9x/ME/NT/2000 or NetWare, we would recommend adding a third party open file manager option (e.g. St. Bernard Open File Manager - http://www.stbernard.com/)
which might cost around US$100 for each workstation and US$300 for each server if open file backup is required.

*Open file option is not required on Linux/Unix/Mac OS X because no files are held exclusively open by applications.