GParted doesn't launch

How did you install? From the ISO?

Why/where is gparted involved?

You wrote

Quote from matefon

I was going through the setup procedure when GParted started to complain

But I don't understand where you used GParted to setup the system.
What did you do, when you got problems?

Have you tried to install gparted on the OMV system? Does not work. You can download the ISO and boot into gparted from omv-extras. But you would only have to do this if you want to resize your OS partition.

So you booted into GParted and got the screen in the first post? You have keyboard and display connected to your server, right?

Quote from matefon

Yes, keyboard and monitor is connected, and I've tried to boot it another time with mouse connected too, but nothing changed, same error/screen.

You could try one of two different things. I've never used the GParted boot option in OMV-extras, because I've always got a Linux USB laying around... Debian, Fedora, Ubuntu, Mint...I've usually got one somewhere.

1. Download a Gparted Live ISO, and use Etcher to put it on your USB. Then boot it and resize the drive. https://gparted.org/livecd.php

2. Just boot an Ubuntu or Mint Live Distro (or really almost any Live Distro), which will have GParted, and use it to partition your drive.

Quote from matefon

Only problem is that my PC cannot boot from USB just CD... So I bought a rewriteable DVD to make this working.

You've got a 64bit PC, that cant boot USB? Are you sure on that? 64bit CPU's have been on the consumer market about 20yrs, and booting USB's has been an option almost that long.

What is your laptop make/model you're trying this on.

Thats not a make model, but ok.

1gig of ram you probably would not have enough ram to boot a live cd anyway

IF IT WERE ME (want to stress that)...

I would download a Debian 9 netinstall ISO and boot it. (Make sure you download 64bit)

Install and use the installer to partition the drive

When it comes time to ask you to install software. Install only SSH server (uncheck everything else or you'll be doing this all again)

Follow the instructions in the guide forum for installing omv on top of Debian 9..

Boot omv, format your spare partition and use.

Another option... if you have an old hard drive laying around (but not enough motherboard ports to support them all)... or one you could zombie from a broken computer/latop/netbook

Hook the zombie hard drive up and use the OMV installer on the DVD to install.

Shut down, disconnect the optical drive and hook the zombie hard drive to it's SATA port.

Boot OMV

Run update-grub as root.

Shutdown OMV

Connect 2nd hard drive

Boot OMV

Format 2nd hard drive (the one you have hooked up now) for use with the webui.

Quote from matefon

Unfortunately I've got 2 old HDD-s but the pc only has 1 sata... (I've got one sata and one ata drive and I can connect the ATA one instead of the optical drive but power cables are different

I guess it depends on how much hassle you want to go through... but usually those power adapters/spliters (assuming it is some type of molex adapter)... are only a a couple bucks at any electronics store. Probably about the same cost as that DVD RW you bought, maybe less.

Edit: Or get a splitter that can share the power going from your current hard drive..