I wonder how it was possible?Hi,
you have damaged your installation!
How looks the output of
UdoCode:dpkg -l | grep pve
		Code:
	
	# dpkg -l | grep pve
ii  corosync                             2.4.2-pve3                     amd64                                                       cluster engine daemon and utilities
ii  dmeventd                             2:1.02.137-pve6                amd64                                                       Linux Kernel Device Mapper event daemon
ii  dmsetup                              2:1.02.137-pve6                amd64                                                       Linux Kernel Device Mapper userspace library
ii  grub-common                          2.02-pve6                      amd64                                                       GRand Unified Bootloader (common files)
ii  grub-efi-amd64-bin                   2.02-pve6                      amd64                                                       GRand Unified Bootloader, version 2 (EFI-AMD64 binaries)
ii  grub-efi-ia32-bin                    2.02-pve6                      amd64                                                       GRand Unified Bootloader, version 2 (EFI-IA32 binaries)
ii  grub-pc                              2.02-pve6                      amd64                                                       GRand Unified Bootloader, version 2 (PC/BIOS version)
ii  grub-pc-bin                          2.02-pve6                      amd64                                                       GRand Unified Bootloader, version 2 (PC/BIOS binaries)
ii  grub2-common                         2.02-pve6                      amd64                                                       GRand Unified Bootloader (common files for version 2)
ii  libcfg6:amd64                        2.4.2-pve3                     amd64                                                       cluster engine CFG library
ii  libcmap4:amd64                       2.4.2-pve3                     amd64                                                       cluster engine CMAP library
ii  libcorosync-common4:amd64            2.4.2-pve3                     amd64                                                       cluster engine common library
ii  libcpg4:amd64                        2.4.2-pve3                     amd64                                                       cluster engine CPG library
ii  libdevmapper-event1.02.1:amd64       2:1.02.137-pve6                amd64                                                       Linux Kernel Device Mapper event support library
ii  libdevmapper1.02.1:amd64             2:1.02.137-pve6                amd64                                                       Linux Kernel Device Mapper userspace library
ii  liblvm2app2.2:amd64                  2.02.168-pve6                  amd64                                                       LVM2 application library
ii  liblvm2cmd2.02:amd64                 2.02.168-pve6                  amd64                                                       LVM2 command library
ii  libnvpair1linux                      0.7.3-pve1~bpo9                amd64                                                       Solaris name-value library for Linux
ii  libpve-access-control                5.0-7                          amd64                                                       Proxmox VE access control library
ii  libpve-common-perl                   5.0-25                         all                                                         Proxmox VE base library
ii  libpve-http-server-perl              2.0-8                          all                                                         Proxmox Asynchrounous HTTP Server Implementation
ii  libquorum5:amd64                     2.4.2-pve3                     amd64                                                       cluster engine Quorum library
ii  libtotem-pg5:amd64                   2.4.2-pve3                     amd64                                                       cluster engine Totem library
ii  libuutil1linux                       0.7.3-pve1~bpo9                amd64                                                       Solaris userland utility library for Linux
ii  libvotequorum8:amd64                 2.4.2-pve3                     amd64                                                       cluster engine Votequorum library
ii  libzfs2linux                         0.7.3-pve1~bpo9                amd64                                                       OpenZFS filesystem library for Linux
ii  libzpool2linux                       0.7.3-pve1~bpo9                amd64                                                       OpenZFS pool library for Linux
ii  lvm2                                 2.02.168-pve6                  amd64                                                       Linux Logical Volume Manager
ii  lxc-pve                              2.1.1-2                        amd64                                                       Linux containers usersapce tools
ii  novnc-pve                            0.6-4                          amd64                                                       HTML5 VNC client
ii  pve-cluster                          5.0-19                         amd64                                                       Cluster Infrastructure for Proxmox Virtual Environment
ii  pve-docs                             5.1-12                         all                                                         Proxmox VE Documentation
ii  pve-firewall                         3.0-5                          amd64                                                       Proxmox VE Firewall
ii  pve-firmware                         2.0-3                          all                                                         Binary firmware code for the pve-kernel
ii  pve-kernel-4.13.13-2-pve             4.13.13-32                     amd64                                                       The Proxmox PVE Kernel Image
ii  pve-libspice-server1                 0.12.8-3                       amd64                                                       SPICE remote display system server library
ii  pve-qemu-kvm                         2.9.1-5                        amd64                                                       Full virtualization on x86 hardware
ii  pve-xtermjs                          1.0-2                          amd64                                                       HTML/JS Shell client
ii  spl                                  0.7.3-pve1~bpo9                amd64                                                       Solaris Porting Layer user-space utilities for Linux
ii  tar                                  1.29b-2+pve.1                  amd64                                                       GNU version of the tar archiving utility
ii  zfs-initramfs                        0.7.3-pve1~bpo9                all                                                         OpenZFS root filesystem capabilities for Linux - initramfs
ii  zfsutils-linux                       0.7.3-pve1~bpo9                amd64                                                       command-line tools to manage OpenZFS filesystems
	Thanks!