Notes about the OSF file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries
, unused processes and other unfavourable system settings to identify slowdown issues.
The OSF file type is primarily associated with 'Descent 3' by Outrage Entertainment. OSF = Outrage Sound File. It would be logical to assume this file format applied to other games designed by Outrage Entertainment as well.