Hi zimbot, my recently updated Ffox 49.0.2 on win Vista plays all of Freesound fine.
My computer just uses the basic motherboard Realtek Audio chip, so nothing fancy to go wrong.
I can only suggest try starting Ffox in safe mode to disable add-ons that might be interfering - or go to "Help" > "Restart with Add-ons disabled".
Hope you work it out,
I have no problem Windows 8.1
Thanks for the replies. Safe mode (no add-ons) doesn't help, nor has killing lots of other stuff running on my system (which is normally there in the past anyway, without having caused this problem). I'm still using XP on this ancient laptop, and it has worked pretty well for over a decade now. I'm pretty sure this must be due to something having changed recently, but I have no idea what. It's very frustrating. Guess I'll try rebooting next.
[Update: rebooted, problem is still there. ]