If you encounter the "explorer.exe command not found" error in Windows Subsystem for Linux (WSL), there is a easy solution to fix the issue.

First, go to the home directory of the current user:

cd ~

Open .bashrc file:

vi .bashrc

Add the following line to the file.

export PATH="/mnt/c/Windows:$PATH"

Save the file and exit.

Use source command to reload the .bashrc file.

source .bashrc