The subprocess.Popen function uses /bin/sh in Unix environments. Android is detected as a Unix environemnt, but has moved that executable to /system/bin/sh. This can be worked around by adding a parameter "executable='/system/bin/sh'" to the call, but it is impractical to do this for every call to Popen in every library and codebase. For subprocess.Popen to work on Android, Popen needs to be able to detect if /bin/sh is not there and try /system/bin/sh instead.