The Snapshots feature in ZenLedger saves your progress. It's handy for:
Making sure that a previous tax year's work is saved when importing new transactions
Ensuring that you can restore when uploading a troublesome wallet or CSV
Restoring from an accidental deletion
You can create your own snapshot at any point in time and label it.
See the video below for a walkthrough of how to use the Snapshots feature to save your work, and to restore a previous version of your ZenLedger account.