When Jamulus starts, it often chooses the "sound card" Device and channels from last time. However, this does not always happen.

What appears to be what's happening is the .ini file only contains a number for the last input/output soundcard combination. That number is based on the list of devices that was built when Jamulus starts up. When Jamulus starts up next time, that same index is used on the NOW current list which could be different. If it is different, a different device is selected

Jamulus needs to store the names of the input sound card and output sound card rather than the index into the current device list. It can then search the device list for the name and select that device.

Also, the device list is only built when Jamulus launches. If a device is added to the list, it won't be seen until Jamulus is shut down and restarted. The ideal solution would be to build the device list each time the device list drops down. If this takes too much time, building the device list when the Settings dialog opens should be sufficient.

I'm also posting a separate issue to separate the device list into separate Input Device and Output Device lists to make setup easier. Search for Separate sound card input and output selection here.