Seagate WD passport not recognised

If you are missing the menu bar across the top of the screen, then that is from using the wrong display resolution.

First try resetting the Mac Min's NVRAM as per > Reset NVRAM or PRAM on your Mac - Apple Support

If that does not help and you can not get to Apple > System Preferences > Displays to change the display resolution, then you need to go to the Monitors Menu that is connected to the Mac Mini and select a different Aspect Ratio.

Click on your Desktop and with Finder on the menu bar, select Finder > Preferences.

In the General tab, check Drives and External Disks

In the Sidebar tab, check Drives and External Disks

Then if you do not see the external drive, then it may have failed.