Truenas 12 - disks can not be used to create a pool

[shotar0815]

Hi guys, I am not a PC newbie, but I am newbie on Truenas.
I installed the system and can access it via Web GUI.
When I try to create a pool, I see only the USB stick with the system but no HDDs.
In "disks" I can see all 3 disks including both HDDs with name, size and details.
Shell and fdisk returns: "mounted root fs resource doesn't match expectations (regexec returned l (or 1?) )"
What can I do?
I already used the dirves to setup an older freenas system - do I need to clear, partition and format and if so, how?
Thanks in advance, G.

 

[Samuel Tai]

Yes, you'll need to remove the partition table in the 3 drives. Assuming they're listed as ada0, ada1, and ada2 in Storage->Disks, the fastest way of doing this is to use the web shell under Shell, and then running:
gpart destroy ada0 gpart destroy ada1 gpart destroy ada2