Error restoring backup "key is duplicated"

[codinghorror (Jeff Atwood)]

That looks a lot like this one:

Update failed due to primary key sequence error

I’ve tried to update from Version v1.9.0.beta4 +300 to 1.9.0.beta5 by pulling the latest changes (git pull) and try to rebuild the app (./launcher rebuild app), but the migration failed with the following message: Any fix? I, [2017-08-11T05:43:33.644343 #15] INFO -- : > cd /var/www/discourse && su dis course -c 'bundle exec rake db:migrate' 2017-08-11 05:43:38.795 UTC [399] discourse@discourse ERROR: duplicate key valu …