Invisible software updates list in Software Updater

Today I received an update notification for three updates but update manager doesn't say what updates are they.

Does anyone have a clue what this is about? How am I to check what is to be updated?

Solution 1:

I was getting this problem after upgrading to 18.04. Preparatory to sudo apt-get upgrade as noted above, I did

 sudo apt autoremove

That resolved the problem for me and 'revealed' what updates were available for download. Almost half-a-gig clogging up the works.

Solution 2:

Don’t worry! I have been through this. To clarify that I did that in terminal with

sudo apt-get upgrade

and it listed the outputs. Only 3 upgrades will be there if I remember correctly.