No need to covert the VDI file to RAW format. Just copy the vdi file into the local folder. For me, I will just put it at /root/testing.vdi
Step 2, Create a new VM in Proxmox
On the “OS” tab, choose “Do not use any media”
On the “Hard Disk” tab, choose “local-lvm”, as storage, Disk size is any size you want, for example, 8GB. Format, choose “Raw disk image (raw)”, On CPU and Memory, choose the same as the Virtualbox settings.
Confirm to create the new VM.
Step 3, Detach and Remove the Hard Disk
Say my VM ID is 109, choose Virtual Machine 109, Hardware, Hard Disk, choose “Detach” button.
At this point, the hard disk will be listed as “Unused Disk.” It still exists but is not attached to the system. To destroy it completely, select the Unused Disk and click Remove again; and confirm when prompted.
I got these errors when trying to run an update on my Proxmox VE 5.3-8
root@pve:/etc/apt# apt update Hit:1 http://security.debian.org stretch/updates InRelease Ign:2 http://ftp.ca.debian.org/debian stretch InRelease Get:3 http://download.proxmox.com/debian jessie InRelease [2,413 B] Hit:4 http://ftp.ca.debian.org/debian stretch-updates InRelease Err:3 http://download.proxmox.com/debian jessie InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C23AC7F49887F95A Hit:5 http://ftp.ca.debian.org/debian stretch Release Ign:7 https://enterprise.proxmox.com/debian/pve stretch InRelease Err:8 https://enterprise.proxmox.com/debian/pve stretch Release 401 Unauthorized Reading package lists... Done W: GPG error: http://download.proxmox.com/debian jessie InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY C23AC7F49887F95A E: The repository 'http://download.proxmox.com/debian jessie InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'https://enterprise.proxmox.com/debian/pve stretch Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.