Shuttle 24TB TB3 won´t switch off

hi there…
i need your help guys

my Gspeed Shuttle 24TB Thunderbolt 3 was working perfectly for about two months now
today i started my imac as always, but the Shuttle won´t show in the external drive section
rebooting the imac, with and without the shuttle connected didn´t help
trying to reboot the shuttle with and without the TB cable didn´t help…
even pressing the OFF button on the back of the shuttle for various seconds didn´t help

i was thinking about pulling the power cable, but i´m afraid it´s gonna do some damage to the drives

what else can i try?
thanks a lot

If the drive is not mounting and the computer is not on, then pulling the power cord is the only way to shut down the power supply and it will cause the unit to reboot properly.

okok… but is it a safe way?
i mean, is there something built in the shuttle, that safely shuts it down as soon as i cut the power supply??
i won´t do any damage to the hard drives just pulling the power supply??

thank you rydia

As long as the OS is not on and the computer is off then it is save to cut the power via the cord.