Addition to Bug #1769770 I tried again, but got the same error. root@walnut:~# apt install grub2 Reading package lists... Done Building dependency tree Reading state information... Done The following additional packages will be installed: grub-gfxpayload-lists grub-pc grub-pc-bin Suggested packages: desktop-base The following packages will be REMOVED: grub-efi-amd64 grub-efi-amd64-signed The following NEW packages will be installed: grub-gfxpayload-lists grub-pc grub-pc-bin grub2 0 upgraded, 4 newly installed, 2 to remove and 0 not upgraded. 2 not fully installed or removed. Need to get 1,043 kB of archives. After this operation, 3,072 B disk space will be freed. Do you want to continue? [Y/n] Get:1 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 grub-pc-bin amd64 2.02-2ubuntu8 [900 kB] Get:2 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 grub-pc amd64 2.02-2ubuntu8 [137 kB] Get:3 http://il.archive.ubuntu.com/ubuntu bionic/main amd64 grub-gfxpayload-lists amd64 0.7 [3,658 B] Get:4 http://il.archive.ubuntu.com/ubuntu bionic/universe amd64 grub2 amd64 2.02-2ubuntu8 [2,568 B] Fetched 1,043 kB in 8s (127 kB/s) Preconfiguring packages ... (Reading database ... 143877 files and directories currently installed.) Removing grub-efi-amd64-signed (1.93+2.02-2ubuntu8) ... Removing grub-efi-amd64 (2.02-2ubuntu8) ... Selecting previously unselected package grub-pc-bin. (Reading database ... 143866 files and directories currently installed.) Preparing to unpack .../grub-pc-bin_2.02-2ubuntu8_amd64.deb ... Unpacking grub-pc-bin (2.02-2ubuntu8) ... Selecting previously unselected package grub-pc. Preparing to unpack .../grub-pc_2.02-2ubuntu8_amd64.deb ... Unpacking grub-pc (2.02-2ubuntu8) ... Selecting previously unselected package grub-gfxpayload-lists. Preparing to unpack .../grub-gfxpayload-lists_0.7_amd64.deb ... Unpacking grub-gfxpayload-lists (0.7) ... Selecting previously unselected package grub2. Preparing to unpack .../grub2_2.02-2ubuntu8_amd64.deb ... Unpacking grub2 (2.02-2ubuntu8) ... Setting up grub-pc-bin (2.02-2ubuntu8) ... Setting up shim-signed (1.34.9+13-0ubuntu2) ... Installing for x86_64-efi platform. grub-install: error: cannot find EFI directory. dpkg: error processing package shim-signed (--configure): installed shim-signed package post-installation script subprocess returned error exit status 1 Processing triggers for man-db (2.8.3-2) ... Setting up grub-gfxpayload-lists (0.7) ... Setting up grub-pc (2.02-2ubuntu8) ... Installing for i386-pc platform. Installation finished. No error reported. Generating grub configuration file ... Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported. Found linux image: /boot/vmlinuz-4.15.0-20-generic Found initrd image: /boot/initrd.img-4.15.0-20-generic Found linux image: /boot/vmlinuz-4.4.0-122-generic Found initrd image: /boot/initrd.img-4.4.0-122-generic Found linux image: /boot/vmlinuz-4.4.0-119-generic Found initrd image: /boot/initrd.img-4.4.0-119-generic Found memtest86+ image: /boot/memtest86+.elf Found memtest86+ image: /boot/memtest86+.bin Found Windows 7 on /dev/sda1 done Setting up grub2 (2.02-2ubuntu8) ... Errors were encountered while processing: shim-signed E: Sub-process /usr/bin/dpkg returned an error code (1) root@walnut:~# -- Best Regards, Avigdor ---- Avigdor Finkelstein Mobile: +972 (0)54 2278452 Fax: +972 8 9316406 Email: