I tried but as you can see in the screenshot there is something wrong, I will try to replace the disks.
Have you tested any of these disks? It does sound like one (or more) aren't healthy.
Try with only one disk so assembling the raid volume isn't an issue. You can either try another factory reset with just one disk installed, or you can remove the partitions on a Windows PC (or zero the disk to return it to a blank condition). The NAS will automatically do a factory install if you power up with an unformated disk installed.
Can you connect the NAS directly to the PC and see if RAIDar then finds it? You'd have to change the PC's IP address to connect that way, but it would at least verify that it's not the Unifi system that's blocking you.
StephenB unfortunately after a reboot no longer gives the option to enter the boot menu. The 4 LEDs remain off even though the 15 seconds with the reset button pressed after switching on have passed. I know something is corrupted
