Make a backup before purging

It's very important that you make a backup before continuing. After you purge transactions or other entries, the only way to view the detail of transactions or entries that were purged from the company file is to restore a backup of the company file.

To ensure that the backup you make is reliable, you should test it by restoring the backup before you purge data from your company file.

It's a wise practice to make multiple backups of your company file -- that is, to keep copies of your company file at different locations. The purpose of multiple backups is simple: backups can fail too. If the backup file is damaged, you're in just as much trouble as you would be without any backup at all. (To make a backup and To restore a backup)