Software Updater broken on 16.04.x

[Bret Busby]

Hello.

On one of my computers running UbuntuMATE 16.04.x, the Software
Updater shows "Updated software is available for this computer. ..."
and "323.1MB will be downloaded.".

But, it now does not display a (selectable/deselectable) list of what
packages are to be downloaded/updated/installed/removed/changed.

This also occurs after the computer is rebooted.

I am not aware of any setting to conceal what packages are to be changed.

What is happening?

-- 
Bret Busby
Armadale
West Australia
..............

"So once you do know what the question actually is,
 you'll know what the answer means."
- Deep Thought,
 Chapter 28 of Book 1 of
 "The Hitchhiker's Guide to the Galaxy:
 A Trilogy In Four Parts",
 written by Douglas Adams,
 published by Pan Books, 1992

....................................................