I just run an apt-get upgrade on my Ubuntu 16.04 installation and I am getting this error:

Do you want to continue? [Y/n] Y
Setting up shim-signed (1.32~16.04.1+0.9+1474479173.6c180c6-1ubuntu1) ...
Installing for x86_64-efi platform.
grub-install: error: /boot/efi doesn't look like an EFI partition.
dpkg: error processing package shim-signed (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)

The output of df -h is

polesemi@pcsensori34:~$ df -h
Filesystem                                          Size  Used Avail Use% Mounted on
udev                                                7,8G     0  7,8G   0% /dev
tmpfs                                               1,6G  9,5M  1,6G   1% /run
/dev/sdb1                                           213G  135G   68G  67% /
tmpfs                                               7,8G  316M  7,5G   4% /dev/shm
tmpfs                                               5,0M  4,0K  5,0M   1% /run/lock
tmpfs                                               7,8G     0  7,8G   0% /sys/fs/cgroup
polesemi@login.dei.unipd.it:/home/polesemi          5,7T  2,1T  3,6T  37% /home/polesemi/homeDei
polesemi@login.dei.unipd.it:/nfsd/signet/ns/polese  475G  266G  210G  56% /home/polesemi/nsDei
tmpfs                                               1,6G  108K  1,6G   1% /run/user/1000

The output of parted is

polesemi@pcsensori34:~$ sudo parted -l
[sudo] password for polesemi: 
Model: ATA ST500DM002-1SB10 (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags: 

Number  Start   End     Size    Type     File system  Flags
 1      32,3kB  41,1MB  41,1MB  primary  fat16        diag
 2      41,9MB  12,6GB  12,6GB  primary  ntfs         boot, diag
 3      12,6GB  500GB   487GB   primary  ntfs

Model: ATA KINGSTON SHSS37A (scsi)
Disk /dev/sdb: 240GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End    Size    File system     Name  Flags
 3      1049kB  212MB  211MB   fat32           efi   boot, esp
 1      212MB   232GB  232GB   ext4
 2      232GB   240GB  8000MB  linux-swap(v1)

What can I do to fix it? Thanks.

  • There may be some help in this question Aug 21, 2017 at 13:46
  • It appears that my /boot/efi folder is not empty
    – Mychele
    Aug 21, 2017 at 14:04
  • Please edit your question to include the output of these two commands: df -h and sudo parted -l. (That's a lowercase -L, not a numeric -1.) Post a comment so that I notice your new information.
    – Rod Smith
    Aug 22, 2017 at 13:43
  • Hi Rod, I added the output of those commands.
    – Mychele
    Aug 22, 2017 at 13:49
  • This issue is still present as of today
    – Mychele
    Nov 8, 2017 at 7:44

2 Answers 2


This problem was solved here: https://bugs.launchpad.net/ubuntu/+source/shim-signed/+bug/1736080 Basically, the /boot/efi partition was not mounted correctly (UUID mismatch in the /etc/fstab file). Once I managed to mount it, the package installed correctly.

  • 1
    What if I don't have /boot/efi in my fstab because my system is not installed in UEFI mode? Aug 18, 2020 at 9:39

Trying to help, Mark

It just happened to me, and the issue was my partitions were "Commented Out" in /etc/fstab.

To check run

cat /etc/fstab

I opened GParted to confirm the UUIDs for their partitions and all were right. Then I "Uncommented Out" all the partitions, and yes they were ALL commented out? Weird!! Restarted Ubuntu, updated/upgraded and the error left.

The command was

sudo gedit /etc/fstab

and to re-iterate for newbies - "Uncommenting Out" means - Take out the the '#' (number signs) in front of the UUID Lines ex

****#****UUID=92a37016-1b32-4743-973e-e792bb3c48ca / ext4 errors=remount-ro 0 1 to read

UUID=92a37016-1b32-4743-973e-e792bb3c48ca / ext4 errors=remount-ro 0 1

I hope this helps, Mark

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