Your data is safe because Simple Invoice offers a backup and restore feature.
Go to the main menu and select Tools → Backup.
There are two backup options in the program: Manual and Automatic.
In manual mode, a backup is created only when the user clicks the Backup Now button.
In automatic mode, the program creates a backup every time it exits. This is the recommended option.
You can also schedule automatic backups while the program is running. Set the interval in minutes as needed.
By default, backup files are stored in the C:\SimpleInvoice folder. You can specify a different location.
Backup files are organized in folders named by date (e.g., 2019-09-01).
Restoring is easy. Just click the Select file to restore button and choose your backup file. Note: this will overwrite and replace your current data.
To move your data to another computer, make a backup on the old machine and transfer the file to the new one. Install Simple Invoice and restore from the backup file. Once complete, your data will be available.
Since version 3.18.1, you can set the backup path to an external drive, USB stick, Google Drive, OneDrive, Dropbox, etc., and restore directly from those locations.