This is tutorial boot proxmox with USB. You must burn file *.iso. And then download a tool that will convert your usb stick into a bootable one (for example, unetbootin or usb universal installer).
Download free ISO images for installing Proxmox VE. To add ISO images to proxmox server, login to server as user root, then go to folder '/var/lib/vz/template/iso'. You can download ISO for operating system you. Browse to the location where you saved the Proxmox ISO file and click on OPEN, click on CHOOSE then click on START. This is tutorial boot proxmox with USB. You must burn file.iso. And then download a tool that will convert your usb stick into a bootable one (for example, unetbootin or usb universal installer. Proxmox iso upload location isn’t hard to find once you know where it is, but it can be tricky initially. Install Proxmox VE server In the Proxmox GUI go to Datacenter.
Run program and choose: “Try Unlisted Linux ISO” –> create.
And then copy file *.iso (of proxmox) to usb.
Boot USB and type : debug (for debug)
When the boot process is completed, you will see a message similar to “no cdrom found – unable to continue (type exit or Ctrl-D to reboot)“
From the console, I’ll simply type fdisk -l.
mount /dev/sdb1 /mnt (note : the /dev/sdb1 represent my stick on my system — Please change this value to reflect your settings)
mount -o loop -t iso9660 /mnt/proxmox_1-7.iso /mnt (again change accordingly based the name of your iso file… )
chroot /mnt sbin/unconfigured.sh
If everything works as expected, you should see the ProxMox VE installer (the GUI basically) and you can go through the wizard to perform your installation.
To add ISO images to proxmox server, login to server as user root, then go to folder “/var/lib/vz/template/iso”. You can download ISO for operating system you need to this folder.

For Debian 10
Proxmox Iso Storage Location
wget https://download.fedoraproject.org/pub/fedora/linux/releases/28/Server/x86_64/iso/Fedora-Server-dvd-x86_64-28-1.1.iso |
Proxmox Iso Location Free
See proxmox