Unfortunately, I was unable to resolve the issue that caused errors on some systems when enumerating available audio devices.
It looks like the reason is in the PyCaw module used in the add-on.
In main repository there are open issues that indicate about this:
So I moved this advanced feature of the add-on to a separate option and noticed it as an experimental feature.
If desired, you can enable this check box in the add-on settings panel, as on some systems this feature still works correctly.
Another strange behavior occurs when using Skype.
When it starts, two or three audio sessions appear, duplicating each other.
So I added a checkbox in the settings panel to be able to hide duplicate audio sessions.
As for adjusting the volume for the Skype process - for some reason it works from time to time...
Unfortunately, I have not yet been able to understand the reason for this behavior.
I have tested the add-on with various programs and I must note that such strange behavior occurs only when using Skype.
Also, one user created a feature request to quickly switching the output to other audio devices:
NVDA has a standard dialog box that allows you to do this, which is called using NVDA+Ctrl+S.
The add-on allows now to quickly switch the output of NVDA sounds simply by pressing NVDA+Windows+PageUp or NVDA+Windows+PageDown.
Updated version of Volume Adjustment add-on is here:
I wish everyone a good week-end!