In order to play the AU files in the MS-Windows version of Mosaic, you will need to: 1) install the "wplany.exe" program and configure it and Windows to work together. The "wplany" program is available in this archive. 2) make sure your mosaic.ini file contains the following lines: [Viewers] ... TYPE9="audio/basic" ... audio/basic="c:\somepath\wplany.exe %ls" ... [Suffixes] ... audio/basic=.au