Early termination of swiss tournament.

When I default to 7 rounds and less than eight people show up, the program struggles with the layout. I had already suggested using Berger tables. Perhaps the disadvantage of this is that people cannot easily join later.
Does anyone have a workaround for this problem? I decrease the number of rounds before the tournament starts and this seems to help a bit, but sometimes the program crashes too, regardless.

By "crashes" you mean it says that there are no possible parings and that the tournament is complete?

Swiss is not round robin, you are expected to have more player's then rounds.

Yes, it gives the message 'all parings are completed'. But they are not completed.
And yes, I have fewer players than set rounds. But it should pair all players to play against each other. But that doesn't happen. The tournament will end prematurely before all pairings are complete. That is the problem.
This problem only occur when you don't have enough players.

To circumvent this you could use Berger tables.

>Yes, it gives the message 'all parings are completed'. But they are not completed.
It says that, because there are no further parings possible. Swiss has lot's of rules about parings.
>But it should pair all players to play against each other.
No. As I said, Swiss is not round robin.
You can read more about swiss here (scroll down a bit) : lichess.org/swiss