Have I read the related troubleshooter articles above before posting (which pages?)? yes
Have I searched the tickets before posting? yes
Have I read the documentation before posting (which pages?)? yes
Joomla! version: 2.5.10, 2.5.11
PHP version: 5.3.19
MySQL version: 5.1.68-rel14.5
Host: Apache
Akeeba Backup version: Akeeba Backup Professional 3.6.12
Description of my issue: status update for your information
Further to earlier ticket by another, #15878 – Updating Joomla 2.5.9 to 2.5.10 DB Error (and my earlier closed #13350 on earlier Joomla versions), the email update link produces the same duplicate key db error.
The good news is that using Extension Manager: Check Database, FIX does now fix the database properly and reports:
"Database schema version (in #__schemas): 2.5.11.
Update version (in #__extensions): 2.5.11."
Maybe the next joomla update will go without error?
Thanks