I guess that's never been tried before...
I very often run RetroFE with no speakers; in fact, in the month or so that I have been using RetroFE, I have never run RetroFE
with speakers of any kind, except to test that this bug only happens when no speakers are plugged in. This is down to the fact that I am still configuring RetroFE and my emulation box, which means I am not actually playing games. When I am configuring this box, I hook it up to a computer monitor. I do not bother to hook up any speakers to it, because I don't need speakers to setup collections, configure emulators, etc... In Linux this is not an issue, in Windows it crashes instantly.
The reason is pretty simple. Windows 10 is only enumerating sound devices that have speakers hooked up to them, and RetroFE is assuming that there is at least one sound device present. Here is the relevant entry in the log file:
[2018-04-07 10:54:41] [ERROR] [SDL] Audio initialize failed: DirectSoundCreate8: No audio device found
I could grab the entire log (its on my emulation box, not my computer) if you really want it, but the rest of the log is just listing out the collections and launchers.