There are 2 kinds of Backups in Quicken, Manual and Automatic. For Manual Backups you can tell it where to put the backup file and if you want to add the current date to the end of the name or to overwrite any existing backup file. If you add the date to the end of the name over time you will end up with a lot of files. In addition to any manual backups you make, Quicken makes an automatic backup after so many times (which you can set). Quicken makes all automatic backups to a folder named "BACKUP" in the same folder where your Quicken data resides.Your data is kept in a file ending in .qdf. So look for files that might have .qdf or .qdf-backup in them. Starting with the 2010 version they added "-backup" to the file extension.To do a manual backup go to FILE - Backup and Restore - Backup or do Ctrl+B. Or I put a backup icon on my toolbar.How to Backup or Restore Quicken Data Files…….
https://www.quicken.com/support/how-backup-or-restore-your-quicken-data