Powerdown is deprecated.  It will not install in unRAID 6.2 because it is not necessary and was not fully tested for 6.2.   I know some people still want to use it, but it has become increasingly difficult to chase down the changes in the shutdown scheme LT implements in each version and for me to try to keep up.  LT has improved the shutdown procedure in 6.2.   I've suggested a few changes to the built in shutdown.  There is no need for the powerdown script in unRAID 6.2.   The webgui