I’ve been looking for the answer to this problem for about a few hours now, but it appears most people seem to only find issue with the stereo/mono of Audacity and not the computer itself.
I am using Audacity v2.3.2 on a Windows 10 laptop. I had been using it for 3 days prior to installing Audacity on it, as I took it to my local tech shop to fix the hard-drive. It should be noted that Audacity (v2.1) worked fine on my computer prior to my hard-drive’s corruption.
Ever since its installation, every time I open up Audacity on my laptop, ALL of the audio cuts out of the left speaker of my headphones. This includes audio from sources that are not Audacity and my left speaker continues to make zero noise whatsoever even after Audacity is closed. These are regular 1/8" jack headphones, not USB headphones or gaming headphones. I thought my headphones had broke, but I used two other sets and the same issue occurred. The only way I have found to set my sound back to normal would be to restart the computer and not open up Audacity again. (On occasion, the audio will be fine until I shift the Audio Host from Windows WASAPI to any other host, upon which the left speaker will stop working and i must restart the computer)
I’ve uninstalled and reinstalled my sound drivers (Realtek High Definition Audio) and updated them to the most recent patch, and I’ve also tried uninstalling and reinstalling Audacity multiple times (I even installed v2.3.1 to see if the issue prevailed). Every attempt failed.
What’s most peculiar about all of this is when I look at the levels for my audio in stereo, there is still sound coming through both speakers. Both are receiving sound, but the left speaker never actually puts any out. I found this out when I was trying to see if I had messed with my computer’s stereo panning by mistake.
I previously used Audacity on a different computer to record audio samples for FL Studio and YouTube. I’ve never run into this problem or any similar problems before.
The most likely problem would be a bad electrical connection. Possibly the connector itself, but usually if the connector is “flakey” wiggling the connection makes it cut in-and-out and you’d know exactly where the problem is. I damaged the socket a laptop once and it had to be replaced. I’ve broken a power connector a couple of times. 
If it’s a hardware problem, the cheapest and easiest fix is to get a USB soundcard. I keep a USB soundcard around for “troubleshooting purposes” so I already had one and that was my temporary fix until I decided to get the laptop “professionally” repaired.
Some computers have “driver utilities” or “sound utilities” and there might be a balance control. (I have the basic “Windows Enhancements” but I can’t find a left/right balance control on the computer I’m on right now.)
On occasion, the audio will be fine until I shift the Audio Host from Windows WASAPI to any other host, upon which the left speaker will stop working and i must restart the computer)
“On occasion” could be a random coincidence.
I’ve seen cases (not on a computer) where there was a bad internal connection (corrosion?) and it could be temporarily fixed by “blasting” the volume. The boost in voltage would apparently break through the corrosion and fix the connection. Something like that could be happening (an electrical burst/impulse) when you switch hosts.
there is still sound coming through both speakers.
It’s going to both speakers, but one of them isn’t working.
That’s not good news.
There is an operational setting which can do that. Do you see the L----o----R slider to the left of the show? If that’s off, the blue waves will seem normal, but the acoustic sound will be off balance.
Otherwise I think you are describing an actual hardware problem.
Koz
I found when pulling the plug in and out while the left speaker was out, at a certain point where the plug was still in the connector but not fully plugged in, the audio would shift to the left side and the right side would be muted instead. I’m thinking maybe this is a hardware problem and not a software problem, considering it also happens when switching to MME.
I found when pulling the plug in and out while the left speaker was out, at a certain point where the plug was still in the connector but not fully plugged in, the audio would shift to the left side and the right side would be muted instead.
That’s kind-of “normal” when the plug-tip (left) touches the ring-contact (right) in the socket. [u]TRS stereo connections[/u]