In most cases, this is because the print server has been installed as a service and additionally opened as a standalone tool.
We do not recommend installing the Print And Scale client as a service.
You can disable the background service by uninstalling then reinstalling without the "Install as background service" checkbox checked.
Double printing could mean two users on your computer have both installed the print and scale client. Uninstall one of the clients to resolve this issue.
If you're still having issues with double printing, check your printer settings or contact support by clicking the orange chat icon to your right.