Gnome Keyring on autologin - disable popup upon login

For Debian Stretch 9 with MATE Desktop but probably other distributions as well.

I suddenly started to get the Gnome keyring popup upon every boot, not exactly sure why but maybe related to some installation.

It told me "the keyring was not unlocked when you logged in" and prompted for password.

There are several solutions for this problem online, but here's what worked for me.

The solution was to clear the password for the keyring, by doing the following:

Make sure seahorse is installed:
sudo apt-get install seahorse

(I also uninstalled libpam-gnome-keyring, not sure if related - sudo apt-get remove libpam-gnome-keyring.)

Run seahorse as the local user:
seahorse

Right click on the Login item in the left panel under Password(s) and choose Change password.

Fill in the password. Then when you get to set a new password - leave both the fields blank(!) and ignore the warning and go on.

And now you don't have any password for your keyring so it can't ask for a password, but the password popup doesn't appear.

Very ironic, it was made to make the system more secure, but instead it resulted in making it less secure by being annoying.

Ubuntu 20 LTS and other - keyring is empty

If you open seahorse and find a message about an empty keyring, try the discrete little arrow in the top left of the window to get out of there and get to the listing of keys. Not sure why they dump the user in that initial view.