Doing a package upgrade via GUI is not working in some situations, due to the latest grub2 updates. the problem is already found and also fixed, but the fix is in the new packages and installing them via GUI will move you into this issue. Best way to workaround the issue do NOT use the GUI for upgrading to latest packages from (pvetest and pve-no-subscription repo), just update/upgrade via CLI (apt-get update && apt-get dist-upgrade) If you already upgraded via GUI and the window disappeared and you have unconfigured packages check your package status via 'pveversion -v' - if you have issues like (not correctly installed packages) do the following: > killall dpkg > dpkg --configure -a This will kill the background dpkg process and continue configuration of all packages, including the new grub2. In order to install grub2, you need to know the device where your Proxmox VE is installed. in most cases this is /dev/sda you can check your device (harddisks) list this by analysing the output of: > parted -l if you want to manually install the grub2 into your MBR (in most cases to /dev/sda) > grub-install /dev/sda Finally, reboot your host to activate the new kernel.