I followed Adam Lindsay's suggestion and looked up \useexternalsoundtrack in core-fig. But unfortunately I am ignorant of low level TeXnicalities. I could only figure out that I needed two parameters and by trial and error I found that they have to be included in [ and ]. The line: \gebruikexterngeluidsfragment[muziek][C:/Downloads/MyMusic.mp3] gave no errors, but not a text `muziek' on which I could click for starting the music. In the past I used the construction \stelprogrammasin[gebied=G:/ConTeXt/Imagine/] \definieerprogramma[PQRS][PQRS.exe][PQRS] \programma[PQRS]. for launching my program PQRS (without opening a file). Unfortunately I could not get Hans' suggestion \naar{programma PQRS}[PQRS.exe] working for this case, maybe because the fs does not support it? Neither could I start my program Sila.exe with a particular file `Sila.spf': \naar{programma Sila}[Sila.exe(Sila.spf)] Maybe I should wait until the coming version. Sytse Knypstra