Sandboxie turns out to be the source of the problem.
- Open Firefox outside Sandboxie
- Type about:config and accept the risk
- Search for “sandbox”
- Switch security.sandbox.content.level to 3 (mine was 4, if needed switch it to 2, 1 or 0 ).
- Close Firefox
- Relaunch Firefox 57 Sandboxed and re-try the audio.
No sound in Firefox 57 (Sandboxie) was last modified: March 27th, 2018 by