Cannot connect to database

[kraada]

Most of these cases have turned out to be cases where PostgreSQL was no longer installed for one reason or another (at least from the remote sessions I've personally done).

[aslakator]

So the easiest way is to uninstall everything and install "full installation"?
Am I able to save my HUD configurations, and how?

[kraada]

Backing up everything is a good idea anyway - you can do that via File --> Backup.

But you only need to reinstall PostgreSQL, as explained on our documentation page. Make sure you install the same minor number that you previously had (if you had 8.3, install 8.3, if you had 8.4, install 8.4).