Error with Update Manager [SOLVED]

[Spiderspoon]

I have Linux Mint 18.3
I am getting an error message when I refresh or open Update Manager for the first time. Screenshot is attached.
Please advise what to do about this.
Thanks.

[all41]

Two things,
perhaps you have added some errant ppa's or,
the mirrors were busy or under maintenance at the time you accessed them.

Open a terminal and enter or copy/paste:

Code: Select all

apt update

Post those results if errors are reported.
Then run:

Code: Select all

mintupdate

Post those results as well.
This will point to your difficulties
Cheers

[Spiderspoon]

Two things,
perhaps you have added some errant ppa's or,
the mirrors were busy or under maintenance at the time you accessed them.

Open a terminal and enter or copy/paste:

Code: Select all

apt update

Post those results if errors are reported.

I've done the first part and following are the results:

john@ASUS-Laptop ~ $ apt update
[sudo] password for john:
Ign:1 http://mirror.aarnet.edu.au/pub/linuxmint-packages sylvia InRelease
Hit:2 http://mirror.aarnet.edu.au/pub/linuxmint-packages sylvia Release
Hit:4 http://security.ubuntu.com/ubuntu xenial-security InRelease
Hit:5 http://archive.canonical.com/ubuntu xenial InRelease
Hit:6 http://archive.ubuntu.com/ubuntu xenial InRelease
Hit:7 http://archive.ubuntu.com/ubuntu xenial-updates InRelease
Get:8 http://repository.spotify.com stable InRelease [3,302 B]
Err:8 http://repository.spotify.com stable InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A87FF9DF48BF1C90
Hit:9 http://archive.ubuntu.com/ubuntu xenial-backports InRelease
Fetched 3,302 B in 1s (2,509 B/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
22 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://repository.spotify.com stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A87FF9DF48BF1C90
W: Failed to fetch http://repository.spotify.com/dists/stable/InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A87FF9DF48BF1C90
W: Some index files failed to download. They have been ignored, or old ones used instead.
john@ASUS-Laptop ~ $

[Spiderspoon]

Then run:

Code: Select all

mintupdate

Post those results as well.
This will point to your difficulties
Cheers

Did that and it opened Update Manager which says that my system is up to date. However, I get the original error message when I Refresh.
So it's not fixed yet.
Thanks.

[gm10]

Run:

Code: Select all

sudo apt-key adv --recv-key --keyserver keyserver.ubuntu.com A87FF9DF48BF1C90

or for a GUI solution go Software Sources > Authentication Keys > Download and add the ID.

[Spiderspoon]

Run:

Code: Select all

sudo apt-key adv --recv-key --keyserver keyserver.ubuntu.com A87FF9DF48BF1C90

or for a GUI solution go Software Sources > Authentication Keys > Download and add the ID.

Thanks. That fixed that problem. I don't know how, but at least it worked.
PS There are 2 options there. I ran the code. Copy and paste code into Terminal is easy.