1-Click addon upgrade fails with "Error updating translations"

[linda_petty@shelter.]

Upgrading from Prestashop 1.6.1.17 to 1.7.4.3
the upgrade process copies files without problems,
does the DB upgrade process (look OK in the logs)
completes the database upgrade process with
'Database upgrade OK'

then it clears caches
then errors with

[ERROR] PHP 1.7.0.0 /* PHP:ps1700_stores(); */
Error during database upgrade. You may need to restore your database.
Error updating translations

I restarted Apache2, then the server but the
the site gave a 500 error at both front and admin end

Any ideas what went wrong and how to avoid this problem?