Error while installing updates 3.0

[technomancer]

This worked for me ! I had to run the command 2 times however for some reason it only gave 2 OK's, after second one it worked.
Thank You aus9

I hope Jerry does not mind making some comments and suggestions?

open a terminal and convert to root by command sudo su
for me, after running apt-get update I see that I do not have the same issue as OP but am on a diff server list....showing above and below results to show no errors

Hit:10 http://archive.canonical.com xenial InRelease                                                                                                 
Hit:11 http://repo.linuxliteos.com/linuxlite citrine InRelease                                         
Hit:12 http://ppa.launchpad.net/nemh/systemback/ubuntu xenial InRelease

suggestion this is one way to fix the GPG errors for technomancer

copy and paste this into your root powered terminal and I show my result

#!/bin/sh
LIST="40976EAF437D05B5 3B4FE6ACC0B21F32  22AAEA0A86A02625 "
for Z in $LIST
    do
  gpg --recv-key $Z && gpg -a --export $Z | apt-key add -
done

Code:

# my result
root@asus:/home/gordon# #!/bin/sh
root@asus:/home/gordon# LIST="40976EAF437D05B5 3B4FE6ACC0B21F32  22AAEA0A86A02625 "
root@asus:/home/gordon# for Z in $LIST
>     do
>    gpg --recv-key $Z && gpg -a --export $Z | apt-key add -
> done
gpg: requesting key 437D05B5 from hkp server keys.gnupg.net
gpg: key 437D05B5: public key "Ubuntu Archive Automatic Signing Key <[email protected]>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg:               imported: 1
OK
gpg: requesting key C0B21F32 from hkp server keys.gnupg.net
gpg: key C0B21F32: public key "Ubuntu Archive Automatic Signing Key (2012) <[email protected]>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)
OK
gpg: requesting key 86A02625 from hkp server keys.gnupg.net
gpg: key 86A02625: "Jerry Bezencon (Linux Lite) <[email protected]>" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1
OK
root@asus:/home/gordon#

If you see 3 successful OKs then run as root command

Code:

apt-get update

and hopefully you have eliminated those gpg errors