I have reinstalled Neon User Edition, and in order to give it more space I made a copy of /home on another hard drive. Then neon was installed over the old installation and finally I mounted the original copy of /home. This means that everything just works as before with all settings and data preserved with one exception: Akonadi won't start up - it seems it can not connect to the database. I am guessing that the new installation of Akonadi created a new database in the new /home which it can no longer reach when I mount the old copy of /home on the other hard drive.

Can I instruct Akonadi to create a new database and use the mail data in my home folder?

If not, what if I uninstall and then reinstall Kontact? Would the existing mails in my home directory be found then?
And if so, which packages would I need to uninstall? kmail, kontact, akonadi-server? anything else?

Update: Poking around in the config files I found the likely suspects: .config/akonadi/akonadiconnectionrc and .config/akonadi/akonadiserverrc:
The newly installed versions both contain references to the folder /tmp/akonadi-claus.vooLM4 while the ones in the original /home refer to a similarly
named folder /tmp/akonadi-claus.Pf6KZT. There is a folder called /tmp/akonadi-claus.vooLM4 on my system, so I tried copying the newly installed version of the files to my /home, but still no luck. It seems that a file named /tmp/akonadi-claus.v00LM4/mysql.socket is missing.