I have been having trouble with Asio4All on my laptop that sometimes the headphones are not available as output and the only solution was to reboot the pc. I found this this advice that may be the solution:  "Right-click the Windows speaker icon in the task bar and select 'Playback Devices' then Disable your sound-card, the 'Default Device' (this may release it for use with ASIO)."  
https://www.image-line.co...vsettings_asio4all.htm

control - Right-click Right-click theSpeaker icon(volume control) on the Windows task bar (lower right) and click Playback devices. Find your 'speakers' (the default device usually) in the list. Right-click Speakers and selectProperties > Advanced. Disable 'Allow applications to take exclusive control of this device'. Restart Windows.