Limit to Single Instance Option

If you enable the 'Limit to Single Instance' option, at most one KeePass instance can be running at a time. If you try to start a second KeePass instance, it is immediately terminated, and the first instance is brought to the foreground.

If the second instance was started using a command line specifying a database to open, and the first instance doesn't have a sub-dialog open, the first instance attempts to close the current database. If this attempt is successful (or if no database was open in the first place), the first instance opens the database specified by the second instance's command line, using any -pw or -keyfile options specified by the second instance. All other command line options in the second instance are ignored.