Undo an Import
You must use the Undo Import
button as soon as you learn there was a problem with importing.

Once you begin making changes,
such as combining duplicate records, or adding and deleting information,
or turn off Legacy, the Undo Import button will no
longer be available. When that happens, you need to restore Legacy from
the latest backup file you made. Please see the article "How to
Restore a Legacy Family File from a Backup Copy in Legacy" at http://support.legacyfamilytree.com/article/AA-00869.
Undo Import will only work if you do an automatic backup before importing. Make sure the backup prompt is turned on by clicking on Options > Customize > 12. Other Settings. On the Prompts/Reminders tab click the button that says Turn On or Off Optional Reminder Messages. Put a check mark in the option Prompt To Do An Automatic Backup Before Merging. Also you won't see the Undo Import button if your Tools ribbon is minimized.
Undo a Merge Session
You must use the Undo Merge
button as soon as you learn there was a problem with combining duplicate records. Immediately cancel the Merge session.

Once you begin making changes,
such as importing, or adding and deleting information,
or turn off Legacy, the Undo Merge button will no
longer be available. When that happens, you need to restore Legacy from
the latest backup file you made. Please see the article "How to
Restore a Legacy Family File from a Backup Copy in Legacy" at http://support.legacyfamilytree.com/article/AA-00869.
Undo Merge will only work if you do an automatic backup before merging. Make sure the backup prompt is turned on by clicking on Options > Customize > 12. Other Settings. On the Prompts/Reminders tab click the button that says Turn On or Off Optional Reminder Messages. Put a check mark in the option Prompt to make a backup before importing into a family file with existing records and also the option Prompt to make an automatic backup when importing. Also you won't see the Undo Merge button if your Tools ribbon is minimized.
No Undo Button
There is no Undo button for deleting records or other operations. Please backup frequently, especially before making any global changes to your family file. However, If you want to undo a mistake you just entered into a field, press Ctrl-Z on your keyboard. Ctrl-Z is keyboard shortcut in Windows applications for the undo command.