Hi-there Karl. Either one of the following approaches should fix the problem.

Approach #1:

1. Navigate to the related directory:

cd "/mnt/c/pulse/default config files/"

2. Retry the same command with sudo:

sudo sed "s/; exit-idle-time = 20/; exit-idle-time = -1/" -i "/mnt/c/pulse/default config files/daemon.conf"

Approach #2:

1. Open the related file in notepad:

c:\pulse\default config files\daemon.conf

2. Manually change the following text from:

exit-idle-time = 20

3. Manually change the previous text to:

exit-idle-time = -1

4. Save the file