Start Process is not working when starting GUI application in WSL on Windows 10 Pro.

I am calling Start Process as follows.

 "yekneb-exec-2" nil
 "/mnt/c/WINDOWS/explorer.exe" "\\\\wsl$\\Ubuntu\\home\\bkey1\\.emacs.d\\yekneb")

According to the Process List this is starting a process but the UI is not being displayed.

  • Does it work if you use a regular single forward slash instead of all those backslashes? Also, if you just try to launch the explorer.exe with start-process without the command line argument of a directory thereafter, does it work for that limited type of use? In addition, I would suggest temporarily using an output buffer such as "*OUTPUT*" instead of nil to help you troubleshoot -- then, check that output buffer for error messages.
    – lawlist
    Aug 19, 2020 at 20:52
  • The following does not work: (start-process "yekneb-exec-2" nil "/mnt/c/WINDOWS/explorer.exe" "//wsl$/Ubuntu/home/bkey1/.emacs.d/yekneb"). Aug 19, 2020 at 20:55
  • This does not work either: (start-process "yekneb-exec-2" nil "/mnt/c/WINDOWS/explorer.exe"). Aug 19, 2020 at 20:57
  • This does not work either: (start-process "yekneb-exec-2" "OUTPUT" "/mnt/c/WINDOWS/explorer.exe"). The buffer is created but it is empty. Aug 19, 2020 at 20:59
  • Dumb question, but is WSL able to run non-WSL programs? If you run that command from the WSL shell, does it work?
    – phils
    Aug 19, 2020 at 22:19

1 Answer 1


I do not know why this works, but I figured out how to get it to work.

(let ((process-connection-type nil)) ; use a pipe
    "yekneb-exec-2" nil
  • Can anyone tell me why setting process-connection-type to nil fixed the issue? Aug 25, 2020 at 0:12

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