Buzzing on play back of scores

Hi,
Often, not always, when I play back a score, there are odd short (less than 1 second) and very audible buzzes. These come quite at random but seem to be less frequent as MuseScore 'warms up' and are usually in the fist 20 or so bars. They are not embedded in any score , meaning that if I replay the score they may or may not occur and if they do they will occur at different places in the score. I can accept that this may be a feature of interference of the sound card on my computer or even the sound system - but I doubt this as the buzzes do not occur when I play music from any other source (iTunes, Musicnotes, YouTube, steaming etc) , but in case it is not, is there any explanation and any way I can get rid of them as they are annoying, especially during performances.