Not sure if this is a strictly TDE problem or not, but I did spend some time trying to restart or reconfigure the sound system. (TCC / Sound & Multimedia / Sound System) When I first got this machine, I did have some problems getting it to work without pulseaudio, as I prefer alsa. Since then, it has been a battle of unseen forces, with pulseaudio and alsa apparently competing for control of my sound. The thing is, music files play just fine (using audacious); online radio usually plays just fine (using qmmp), although I sometimes have to go into settings and enable pulseaudio. (It will buffer up, then the stream dies.) But usually this is just a bit of playing round, then it works. My videos are a constant headache, though. I don't watch them much, but when I do sometimes want to watch something, suddenly I don't have sound, and it doesn't seem to matter what I use, pulseaudio or alsa. Also, when I had similar problems before, it only took some configuration, then it worked again, and I never gave it a thought after that. This problem keeps popping up, with no apparent rhyme or reason to it. My videos won't play sound. Doesn't matter if I use smplayer or vlc (which are my two main programs for videos). It used to be that some videos would only play on vlc, some on smplayer. Other programs were also hit-and-miss. Now no videos will play sound, on any program. I've also tried nearly every other program available for videos. I've downloaded all codecs that seem to be required. (I save downloaded packages, and use dpkg to install, then just upgrade periodically; so I know what I used before in my working configuration.) I've done this time and again, in previous installations, and usually no problems after getting everything set up. With this new laptop, the sound in the videos disappears sometimes with every new reboot. The only major change in my system is that I bought a new toy; a Focusrite interface to attach musical instruments (guitars, keyboards, microphones, etc.) to my laptop via a USB interface. (I used to have a line-in jack in my old desktop, so I just plugged in via a headphone amplifier.) It took some messing round, but I got this device working, so I can play through my speakers, or record to the machine using audacity. Sometimes I have to make changes to make sure that audacity isn't claiming the sound system. However, I have shut off everything else that could interfere. No active music files, the Focusrite audio interface is shut off, etc., etc. And still, I have no sound in any of my videos; doesn't matter what format, doesn't matter what program I use. I would guess that it is a TDE problem, since I booted into xfce, and the sound works fine in that desktop. However, I don't like to spend time there, and don't want to use it except for testing. Anybody have a clue about what is wrong? As I said, it is all rather hit-and-miss. Sometimes the sound works, sometimes not. My installation and programs installed or used, etc., have remained the same since December 2021. I've been running the same programs on other machines for at least 15 years now, so I like to think that I know how to track down and resolve most issues, but this one just keeps returning. Sorry for the length, but I wanted to include all possible details that could be relevant. Please feel free to trim in the responses. Any help will be appreciated. Bill