Widraz Have you disabled Secure Boot (or something similar) if your computer has it, that could cause similar problems?

      jwhuettl Yes I disabled it. The USB boot is activated and my USB key is at the first place on the boot list

          Widraz This may be a stupid question, but who did you manage to install it in the first place then?
          Just follow the same steps you did before when you installed alongside the other operating system, but check the option kyrios pointed. Then you'd have everything settled.

                EQLucky I followed the same steps I did before but it didn't work. And I don't know why

                    It was a dual boot system. I deleted the Windows partition

                      Widraz It was a dual boot system. I deleted the Windows partition

                      How ? Because I'm starting to suspect that something got left behind.....

                      Widraz Yes I set it up with Rufus with the Solus ISO

                      Yes it has been set up properly and yes it's working properly ? Have you tried it on another system ?

                            Widraz
                            And that left what on the disk ? We can't go on all day like this, describe in detail what you did, how you did it, on what (ie : hardware specs of your still unknown system) and then perhaps a solution could be found.
                            Otherwise, a neverending stream of one liner answers we'll get us nowhere.

                                CorvusRuber

                                CorvusRuber Here is what I did exactly step by step. I had Solus OS and Windows 10 in dual boot and I prefer Solus OS so I wanted to give the space of theWindows partition to Solus. So I launched Solus, opened Gparted and deleted the Windows partition and Gparted put the me that space as unallowed space. Before that I had prepared a USB device with the Solus ISO prepared on it with Rufus. In the BIOS I allowed USB boot, disabled secure boot and put the USB device as the first one to boot (before my HDD). My PC detects the USB device but just puts on the screen "reboot into firmware". Do you understand better what I did ?

                                • sgvd replied to this.

                                      If you still have Windows. Try to make a bootable usb with YUMI.

                                        Widraz
                                        Can you show us (screenshot) what you see in Gparted in the pc's current state? A screenshot would show the exact state of your disk, which can help debugging your issue more reliably than messaging back and forth.

                                        It's even possible that, since you didn't specify it in your steps, it could be that you simply forgot to apply the changes in Gparted (this happened to me once as well, since Gparted already shows it as 'Unallocated' before you apply the changes).