After installing the hardware and software, my hdd 1 is inactive. I swapped my disk 1 and 5, 1 is still inactive. I checked my connections in the box but I don't see any problems. Could this be due to a software error?

Do you use M.2 slot? That one is shared with a sata slot. Cannot use both.

From the wiki:

Quote

The M.2 SATA bus is shared with SATA Port 1, therefore if you install an M.2 SATA SSD card, SATA Port 1 (J3) will automatically get disabled.

Source: https://wiki.kobol.io/helios64/sata/#sata-controller-diagram

@Julien Michel

Could you try to swap SATA port 1 and port 2 on board then check if now the HDD slot that has issue is slot 2 ?

This way we can narrow down the issue.

I had a similar problem,  I worte the following to the kobol support:

 

The problem is the thread hole that is not done very well, and the screw does'nt enter easily.
I tighten very hard the screw with hexagon head, this one:
https://wiki.kobol.io/helios64/img/kit/assembly_pic30.png

 

And now all the trays is working.